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In Figure 40, the stations are numbered sequentially from 1 to 14 in order along the route, beginning with DIA, and ending with Eagle County Airport.
1. DIA
Verification that this decomposition was successful is shown by summing the eastbound and westbound flows for each station. The result of this process is shown in Figure 41, proving that the decomposition has been successful.
Completion of this procedure provides the data necessary to operate the simulation.
In the simulation, passengers are drawn at random from the pool of those available in the station at any given time, and loaded onto trains. The trains are then moved to their destinations, and the passengers disembarked. Statistics are maintained and resource conflicts are identified. In the end, the results show the necessary train traffic needed to meet the demand during the peak period, and confirmed the operating headway projections, requiring dispatch no more frequently than 150 seconds. Only a few resource conflicts were noted during the simulation runs, indicating that the system was not near full capacity. Additionally, the three or four conflicts that did arise were easily resolved by minor departure delays.
Colorado Maglev Project Part 3: Comprehensive The results for the peak winter operating times are shown in the following figures. As shown, the numbers of trains operating at any interval of the time period are shown according to the station of origination, coded again by serial number, as before. Trains are recycled as they become empty, so that the maximum number of trains needed to carry the load has to be counted by counting individual trains. This count requires approximately 75 trains in service during the peak, in rough agreement with the manual fleet estimates. 5. examined structural lifetime and maintenance issues associated with the trusses; and 6. developed recommendations for the lowest cost mechanisms for producing these
No attempt has been made in this simulation to optimize the number of trains. Instead, trains are added as necessary to meet the waiting time restrictions at each station, and each train stops at every station to take on passengers, i.e., this is local service only, with no express trains. It is certain that the optimization of the movement of trains would marginally reduce the number of trains required, achieving both capital and operating cost economies.
Figure 42: Eastbound Trains on a Winter Saturday Morning
Figure 43: Westbound Trains on a Winter Saturday Morning
R15 HIS HIS HIS H16 H16 H16 H15 H11 H17 H11 H17 H18 H18 R18 R18 R19 19 #19 R19 20 H 20 H20 H20 H21 HZL H21 Q1 Q2 03 04 91 az Q3 24 21 22 23 0:4 0:1 fine Q3 Q4 Q1 Q2 Q3 Q4 21 22 23 24 21 Q2 Q3
Figure 44: Eastbound Trains on a Winter Saturday Afternoon
HIS H15 H15 H15 R16 H16 7:15 H15 H17 #17 HIT 117 118 118 118 H18 119 H19 19 19 20 H20 H 20 20 21 21 Q:1 22 Q3 6:4 021 0.2 Q3 0:4 1 Q2 Q3 Q4 G::2 Q:3 04 Q1 :2 0:3 Q:4 2.1 Q2 Q3 Q4 Q1 23
Figure 45: Westbound Trains on a Winter Saturday Afternoon
One of the potential outcomes of further simulation is a cohesive strategy for the management of vehicles that have discharged their passengers, together with requirements for guideway switches and storage and staging facilities for vehicles needed to implement the strategy. These objectives could be pursued in the next stage of system design of the CMP.
3.3.1. Route Characterization of the guideway route required considerable effort. This was necessary due to the many different forms of available data describing the conformation of the 1-70 corridor and the need to produce a guideway that could be constructed at minimum cost. A thorough review of all data sources indicated that an independent GPS dataset would be required to verify the integrity of multiple sources. The GPS data was collected and reconciled with the CDOT PEIS dataset. The guideway was then sited in the median of 1-70 and a full guideway dataset was produced for the research effort.
There were two basic reasons for the choice of median siting. First, the research would not become encumbered with discussions of land acquisition, which could be contentious and would potentially cloud an assessment of the system cost. Second, the PEIS effort had identified
Colorado Maglev Project Part 3: Comprehensive
environmentally sensitive areas along the corridor and the analysis could benefit directly from this knowledge without having to undertake the same effort in unstudied areas of the corridor.
However, completion of the route dataset did provide an opportunity for evaluation of alternative routing in the tunnel areas of 1-70. The evaluation took into account grades, tunneling costs, and climate issues, but did not address land acquisition or environmental sensitivity. This effort led to the establishment of a potential alternative route at Kermit's Bar, just east of the Idaho Springs Twin Tunnels. Further, an elimination of the transit bore at the Eisenhower Tunnel has also been evaluated using the grade climbing capability of the maglev system to cross the Continental Divide, over the area of the Eisenhower Tunnel. For purposes of the system design, identification of these alternates was intended to demonstrate that many tradeoffs must be considered carefully before a final route is selected for any system deployment.
Completion of the route dataset also permitted the computation of maximum kinematic vehicle velocity over the route, consistent with passenger ride comfort constraints. This theoretical maximum speed along the route was in turn used to establish best-case travel times between all station pairs. These times were useful in the simulation activity, which proceeded in parallel with the propulsion trade study.
In future studies of the corridor, this velocity profile would also serve as the starting point for optimization of the route itself, as opportunities for travel time reduction, increased ride comfort, or operational efficiency are further studied.
Further, this guideway dataset and its associated kinematic velocity profile have been used as the point of departure for the Project's propulsion and simulation studies.
3.3.2. Guideway Design Substantial effort was devoted to guideway materials review and analysis. Guideway development in Europe and Asia has produced workable guideway solutions, although guideway cost optimization is still not complete. In particular, lowered cost guideways intended to meet the civil structures lifetime requirements, while preserving acceptable maintenance profiles, still require development.
The primary issue in maglev system guideway structural design is deflection. The weight of the vehicles compared to the guideway structural weight is such that the designer must primarily search for a way to produce a lightweight, stiff structure at minimum cost. This search naturally leads into lightweight steel structures, since steel is roughly three times stiffer than alternative metals. Concrete solutions, although cost effective, have other issues including weight, creep, and operational limitations (potential snow and ice buildup) in harsh environmental conditions.
The results of this analysis have pointed to tubular steel space frame trusses as the guideway system most likely to satisfy all the system requirements in Colorado. Structurally, this design is the most economical in its use of materials, with a ratio of strength to weight higher than that of any alternative structure. The integration effort has focused on a thorough examination of the cost issues associated with this result, since the initial cost of this type of structure may potentially be slightly higher than the costs of concrete or steel box beam structures used to achieve the same result.
The effort has: 1. identified viable suppliers of the materials for construction of these trusses; 2. sought the advice and processes of fabricators who could assemble these materials into trusses for both straight and curved sections; 3. obtained probable costs from both sources; 4. reviewed material handling and assembly techniques through the entire truss manufacturing process;
Because the Colorado system would require more than 16,000 of these trusses, this cost is a central element of system capital cost; accurate definition of this cost is a critical integration task.
3.3.3. Tolerances Careful examination of the necessary tolerances for guideway alignment has led to analysis of techniques for achieving the necessary accuracy in guideway placement. Two factors have influenced this analysis.
First is the experience that, once aligned, the guideway can maintain its alignment over a long period of time. In this regard, it is not like the high-speed train systems, Shinkansen and TGV, which require continuing and extensive track maintenance. So, for example, the Nagoya test track of HSST has required only minor incidental maintenance over a period of nine years.
Second is the experience that the largely manual initial alignment during construction is extremely labor intensive and time consuming. This alignment has been conducted so far with traditional surveying instruments, basically transits and tapes. This approach is challenging in complex curves and needs to be replaced with more modern, electrooptical, techniques. The use of new techniques for this construction task will improve accuracy and reduce costs.
The integration analysis has disclosed real opportunity for reducing the labor cost during the construction process. In the construction processes, the greatest leverage comes from focusing on those structures employing steel members. Two of these have been put forward: one based on a prefabricated steel box truss, and the second on a prefabricated steel space frame truss. Either type offers the prospect of automated construction, and therefore, prealignment of rail attachments to the truss. The truss, with aligned rails, can be transported and installed with only limited final alignment in the field. This contrasts sharply with concrete construction, where a rapidly steam-cured green concrete beam must cure for a considerable amount of additional time, a creeping all the while. Only when it has been erected and the precast deck put in place, can the creep be evaluated and the rails installed. The rails and sleepers must be installed and shimmed as a unit, rechecked after a period of time to verify that further creep has not destroyed the alignment, and readjusted if necessary.
3.3.4. Construction Issues The integration effort has also dealt with issues of guideway construction that are separate from the materials issues of guideway elements. Chief among these construction issues are transport of large, prefabricated, pre-aligned guideway components to construction sites, and erection and alignment of guideway structural elements. The reasons for treating these as integration issues is to ensure that cost integrity is preserved through the estimation process, as well as to ensure that important system attributes in the vehicle/guideway interface are not compromised by the construction process. Examination of these issues early in the process can help to assure a consistently usable guideway. As the largest item of capital expenditure in the project, it is important that guideway integrity and functionality not be compromised by unforeseen conditions. This has happened repeatedly in early maglev projects and cannot be tolerated in a project with the scope of the Colorado initiative.
The sizes of girders that must be transported range from 20-30 meters in length. The upper range of these lengths is likely to require special handling in over-the-road transport to insure that such long girders are not a hazard to normal traffic. These lengths are at the upper limits of handling for this type of transport, although they can be handled with appropriate care. The
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The CMP guideway is roughly 250 kilometers (155 miles) long. Fourteen potential station sites have been identified. These stations will provide the proper functions of typical transit stations including:
All the station designs are planned to be consistent with the character of the buildings in the area of operation or predicated on the local area desires where each station is located.
The station subsystem must meet certain performance requirements. Specifically, it must support the safe movement of passengers through the station at specified flow rates and must also support particular levels of vehicle traffic.
3.4.1. Locations 1. DIA (DIA, mile 0): This station represents one terminus of the entire system, serving DIA. 2. Rolla (96th Street & 1-76, mile 16.6): This station serves the developing north Denver area, potentially connecting with other transit presently under development. 3. Downtown Denver (1-70 &1-25, mile 25.0): This station is located at a major transportation interchange, and will capture a large portion of riders coming from the northern Front Range cities, including Boulder and Fort Collins. 4. Golden (1-70/Colfax Avenue & US 40, mile 37.0): This station would serve as the collector for riders coming from South Denver, Pueblo, and Colorado Springs. 5. Evergreen (Bergen Park/Route 74, mile 47.4): This station would provide access to Evergreen Park recreation area, and also serve numerous small, urbanized areas along Route 74 to the south. 6. Idaho Springs (mile 59.0): This station would provide access to this historic mining town, and also serve local population in the town and in the surrounding canyons. 7. Georgetown (mile 70.7): This station would serve three small communities of Empire, Georgetown and Silver Plume. 8. Loveland Pass (mile 82.4): This station would provide access to the Loveland Ski Area just east of the Continental Divide. Silverthorne and Dillon. There are areas of scattered residential development all along Route 9 and US 6. These routes also provide access to Keystone Resort, Arapahoe Basin, and Breckenridge Ski areas. Area. 11. Copper Mountain (Wheeler Flats, mile 103.3): This station would provide access to Copper Mountain Ski Resort, and serve residential development along Route 91 as far south as Leadville. 12. Vail (mile 122.5): This station would serve communities of Bighorn, Vail, and West Vail; Vail Ski Resort; and residential development south along US 24. Page 4
vehicle motor can be optimized to meet the required performance characteristics. The results of this analysis are shown in Section 6.0 of this document, the Propulsion Trade Study.
3.5.3. Critical Subsystems The integration analysis has shown the propulsion subsystem to be the most critical of the vehicle subsystems. The original motor in the HSST 200 vehicle simply did not have enough power, and hence could not provide the necessary thrust to meet the Colorado requirements. Various propulsion alternatives were considered during integration, but all analysis showed that a new LIM would be the best alternative. Fortunately, CHSST had a more powerful LIM under development, and the propulsion trade study has now shown that this motor can be configured to meet the requirements. Next in priority of criticality would be the levitation subsystem, although analysis and testing has shown that this subsystem should perform well within specification. Other subsystems, such as the command, control, and communications subsystems (CCCS) have been proven in operation on other transit properties.
Hence, the question of vehicle adequacy appears to be settled, and the Colorado 200 vehicle represents an entirely new maglev capability: the urban/suburban/rural medium speed, medium capacity train. The vehicle is reminiscent of aircraft technology in both concept and in operation, and should be well accepted by the traveling public. The short time that it would take to deploy this vehicle, since only modification of an existing machine is required, is also a real factor in its favor, along with its technical characteristics.
Fortunately, the CHSST system is control-neutral. Until this study effort, CHSST systems had always been put forward with fixed block controls and manually operated trains. CHSST has shown a willingness to embrace more modern controls, and the vehicle control interfaces appear to be compatible with many different control approaches.
It is fortunate that moving block systems are just now coming into operation in several parts of the country. The most promising of these for the CHSST system appears to be the system developed by the Bay Area Rapid Transit District (BART). This system relies on packet radios and vital wayside computers and circuitry to achieve brickwall headways presently limited to 90 seconds, with the opportunity to safely further reduce this number in the future as technology improves. From the simulation results, it appears likely that the CMP can be operated during peak periods at 120 to 150 second headways. Given the demonstrated capability of the BART control system, it seems straightforward to meet or exceed the Colorado operational goals without stressing the controls.
The BART control system is schematically described in Figure 49.
Colorado Maglev Project Part 3: Comprehensive
The partition of function places the station control computer(s) at the center of the hierarchy. Based on the service schedule communicated to them by central control, each non-vital station computer manages the vehicles in its region of responsibility. A non-vital processor deals with schedule issues and speed commands to maintain service. A vital processor deals with safe train positions and speeds, and with interlocks (doors, switches, etc.) All these elements are fault tolerant, employing primarily checked redundancy to insure continuous operation. In addition, the vital elements have had special techniques and methods applied to insure that they can only fail in a manner which places the system into a safe state.
Position and velocity information are derived from measurements taken dynamically on and from the cars using radio propagation delay techniques. A series of wayside radios along the track maintain constant communications with train radios, permitting the measurement of signal delays as the information reaches each end of the train. The times of transmission and receipt are known, and since the transmitter positions are also known precisely, the differences in these times can be used to provide precise measures of instantaneous train speed and position. The station computers use this information as their criteria for actions.
This information is also available to control equipment on the train. However, the train controls also make use of independent tachometer and accelerometer data collected directly from the train itself. This information provides a primary verification of information derived from radio propagation. If there is any indication of over-speed or other problem, the on-board control can act independently to place the train in a safe condition, i.e., apply brakes.
While this system is simple in conception, there are many details that require careful thought to resolve correctly. It is a tribute to BART that they have managed to complete the development of this control system and put it into certifiably safe operation. This type of system is economical and offers a high level of performance and safety.
Due to the prospective costs, it was necessary to evaluate the electrification of the system in detail. With the help of CHSST and Sandia National Laboratories, wayside subsystems and rectifiers were specified for costing with the designs reviewed by power engineers. The result of this activity was a workable design for wayside electrification, together with a cost scenario usable in the context of the total system cost. Previous review of the electric utility situation in the corridor had disclosed a shortage (or total lack) of transmission capacity along the route. Discussions with utilities and industrial electrical equipment vendors made it clear that the permitting process to add transmission facilities to the corridor would be a long and arduous process, conceivably lagging behind the construction of the maglev system. As a result, consideration was given to the potential collocation of the transmission facility with the guideway. This approach was enthusiastically accepted by the utility companies providing electricity in the corridor, since these utility companies have been seeking new transmission capacity to serve the growing population and economic activity of the 1-70 corridor. All agreed that a successful effort to use the guideway route for additional electric transmission facilities would be a valuable supplemental benefit from the construction of the maglev system. Several indicated interest in financial participation in the system if this proved technically feasible.
This concept was pursued, even though it was clear that it might also face regulatory issues. It was felt that the technologies available might provide a unique way of meeting those issues.
First, it is now possible to routinely consider undergrounding 115 kV transmission facilities. Several of these undergrounding concepts have been proposed in other states, some involving considerable distances. These designs have been based on advances in electrical insulation technology, using a number of different technologies. One relies on new cable technology , employing cross-linked polyethylene insulation. There is long experience with this material in Germany, for example, and it seems clear that some use could be made of this technology for solving some undergrounding problems.
However, in the 1-70 corridor, full undergrounding of the electrical transmission system is probably impractical, due to a wide variety of factors, such as geologic and environmental conditions, regulatory issues, and costs. Because of these considerations, full undergrounding along the entire guideway route is not a feasible option, although it might prove useful for the solution of some specific engineering problems in limited portions of the alignment.
Second, there may be a way to carry the required transmission capability on or within the guideway structure itself. This type of approach is more speculative because the structural implications are not fully understood. But, there is the well proven technology of the gas insulated transmission line (GIL), developed and proven in Europe and the US over the last 25 years, and this technology is likely adaptable to electrical transport on the guideway structure.
These lines have remarkable safety, structural integrity, electrical capacity and characteristics, and excellent durability. They appear to be fully compatible with other guideway materials, and may even help to mitigate some of the other safety costs associated with necessary guideway functions.
Their operating principles are simple: a coaxial transmission line is constructed with the current carrying conductor configured as the central coaxial element. The central coaxial element is suspended by insulators in an outer metal pipe and then the assembly is filled with a stable insulating gas mixture of 80% nitrogen and 20% sulfur hexafluoride. The resulting assembly is mechanically rugged, thermally stable, and can safely carry huge currents at voltages ranging up to 1200 kilovolts. Because of the coaxial geometry and insulating gas characteristics, the line has low capacitance and, unlike overhead cable transmission systems, has low degradation and sensitivity to environmental conditions over time. These characteristics make it an option for use in the CMP, although the cost may be more than other alternatives. It should be noted here that tabulation of these costs is beyond the scope of the current effort.
A second transmission technology, employing dielectric-insulated cables, is also feasible for the transmission of the needed power along the guideway. Using cross-linked polyethylene insulation, voltages up to 345 kilovolts can safely be carried in underground trenches. There is long experience with this type of insulation, also pioneered in Germany, and it is reliable with long service life when protected from UV radiation. Carried in grounded conduit, this technology may have a cost profile better suited to the overall project.
With either transmission technology a safe way to carry the transmission lines, from auxiliary towers or suspended from auxiliary beams, would have to be found. This is routinely accomplished with bridges and some of those techniques may be applicable to the Colorado Project. However, this approach represents an engineering challenge. Conceptually, there is a way to suspend the needed transmission facility with the emergency egress girder, perhaps even taking advantage of the structural characteristics of both to achieve a stronger guideway. If this can be done, the guideway costs attributable to emergency egress can instead be partially absorbed as system infrastructure costs attributable to the primary electrical transmission system.
Clearly, this represents a direction for future research in guideway design. This preliminary technology identification effort has confirmed that one of these technologies can probably meet the power transmission requirements for the CMP
The question remains as to whether existing electrical generation has the capacity to support the maglev system operation. Pending resolution of this issue through further study, it is probably sufficient to point out that gas turbine power plants located along the alignment could provide the needed power. Such plants are economical, reliable, and now with newer approaches, even offer acceptable emissions control. With correct design, this approach could provide excess generation and transmission capacity, which could be shared with the utilities for use in serving new growth in electric demand in the corridor; revenues from this source could also help to defray maglev system costs.
Generally speaking, power plants are much easier to permit than transmission lines because they are geographically confined to one place, and the environmental impact is restricted to other considerations. In particular, emissions are a critical factor in modern power plant operation and this would be particularly important at altitude. There are new processes for removal of NOx and
these processes are well tested. Typically, a well-run turbine generator can now achieve 0.5 ppm NOx, and effective heat exchangers are also available for waste heat recovery. The cogeneration aspect of a local power plant would be welcome in many mountain communities in the corridor, who could also make good use of both the waste heat and the off-peak power generated.
These plants are economical to purchase and to operate. Their reliability is superb and they can run for long periods with only routine maintenance. First class installations can be procured and installed at between $30M and $50M each. However, there are a collection of issues which could prevent serious consideration of this alternative.
The chief problem with this alternative is the location of an adequate fuel supply. These units run from natural gas. Natural gas is not particularly plentiful in the United States, although there are strategies such as coal gasification that might be feasible in Colorado; there are plentiful supplies of coal and oil shale in Colorado. However, there are two large natural gas basins located in the adjacent states of Wyoming and New Mexico, as shown in Figure 50, taken from http://www.energy.ca.gov/naturalgas/western state pipelines.html:
The Rocky Mountain Basin and the San Juan Basin are in reasonable proximity to Eagle County Airport. There is a major pipeline connecting these two fields, and there is a compressor station in western Colorado, midway between the two fields. To serve power plants in the 1-70 corridor, it would be necessary to construct a connecting pipeline from the compressor station to the Eagle County Airport vicinity, where the first plant would be sited. Then, the pipeline would have to be carried to the next site, say Frisco, using the guideway right-of-way. A third plant could be located in the Idaho Springs/Georgetown area.
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For hypothetical purposes, this resolves the power issues for the maglev system, and benefits the mountain communities by increasing the quantity and reliability of their power sources, thereby benefiting the Colorado economy. However, there are several practical considerations, which make this alternative less attractive.
First is the altitude. This has the effect of reducing the efficiency of the power plant, and secondarily of placing more emphasis on emissions control. Power plant engineers who have examined these scenarios have indicated that at 1980 km (6500 feet), the approximate altitude of two of the hypothetical sites, the relative efficiency loss could amount to 10%, which is a tolerable derating. However, at 2600 km (8500 feet) or more, the altitude of several potential sites, the derating climbs rapidly, requiring careful consideration from the standpoint of fuel efficiency, emissions, and cost/benefit.
Second, these plants require a significant amount of water for their operation. This water is used for cooling and is evaporated directly to the atmosphere, and is thereby lost. While wastewater can be used for this purpose, the implications for water may be the most important issue this concept faces. A new technology for secondary generation through waste heat recovery by propane cycle heat transfer may significantly influence the demand for water cooling of conventional generators.
Third, there is considerable cost associated with pipeline construction. It should be pointed out, though, that there also is cost associated with new electric power transmission lines. One way or another, providing energy to operate the maglev system will incur cost. How this is to be accounted for is an open issue, since this increased capacity might be considered as an infrastructure improvement for the entire corridor.
Finally, there is the cost of fuel for plant operation. The price of natural gas is subject to fluctuations and is entering a period of increasing prices, due strictly to supply/demand characteristics. It is not likely that this situation will stabilize in the future, and it may in fact worsen. Strong demand from the eastern US has stimulated the gas fields to produce increasing quantities, and the long term stability of the fuel supply for gas fired plants would have to be studied carefully before it could be recommended as a viable power source for the CMP.
At this point in the research, ways to obtain the electrical power needed by the maglev system have been identified, and are feasible at some level. Regulatory and other issues would have to be studied further, along with additional study of the technical tradeoffs, before a firm recommendation as to power source could be made. Suffice it to say, there are ways to generate and deliver the needed power, although there are challenges to accomplish this in an economically secure manner. This situation mirrors the overall general situation for power consumption in the United States as a whole, wherein secure sources of electrical energy must be provided economically to support future economic growth.
As part of the research effort, a comprehensive examination of security issues was conducted. The results of this effort are described in section 9.0 of the CMP Final Report. Since this analysis was completed earlier in the project effort, attacks have occurred in Moscow and Madrid and there have been reports of terrorist planning for the targeting of other urban mass transportation systems, specifically mentioning London and New York subways. One must also believe that Chicago is additionally targeted because of its unique underground structure.
A further safety and security consideration unique to Colorado has come up in later stages of the integration effort as the reliability and maintenance approaches have been studied.
Colorado Maglev Project Part 3: Comprehensive To meet reliability goals for the system, it is essential that a specific maintenance approach be followed. This approach requires that a certain level of maintenance be conducted in the stations, rather than in the maintenance facility. Conducting such activities in stations implies that the stations must be designed to accommodate the activity, meaning that some form of vehicle storage/access for maintenance is available.
This adds to station cost, and would not be pursued in a standard system design. In a standard design, maintenance facilities would be strategically located in the system, and vehicles would be stored either on-line, or on spurs at these facilities. In Colorado, this would be an unwise strategy. The prevalence of high-powered firearms in the state and their use in vandalism events makes open storage of vehicles unwise for this particular system.
The alternative, of course, is distributed storage in the stations. In this concept, each station would have storage positions for as many as six trains, three in each direction, with a transfer table supporting the movement of trains from one track direction to the other. One position (the center position) would be used for normal docking operations, while one would be used for maintenance, and the other for switching through the transfer table mechanism.
Overall, this approach is likely to be less expensive than the conventional approach, due to the relatively low cost of docking mechanisms, which would be used for both normal and transfer operations. This approach, correctly implemented, provides redundancy in docking operations if necessary, although it does present a station design challenge.
3.9. VEHICLE/GUIDEWAY INTERFACE A thorough analysis of the vehicle/guideway interface has been conducted during the integration effort. All dimensional clearances and tolerances were reviewed, together with constraints for modification of the propulsion system, imposed by the interface. The conclusions of this analysis were that the interface, with suitable modifications for power collection, would be serviceable in the Colorado system.
A simmering issue in the vehicle/guideway interface, first addressed in the propulsion trade study, is the magnetic permeability of the rail itself. This has been little characterized in all past systems, so far as can be discerned, and is a ripe area for further optimization. This fabrication parameter has considerable influence in the interaction between the rail and the motor, and can drastically affect the efficiency of the interaction.
3.10. ANOMALOUS CONDITIONS
Anomalous conditions are any conditions that cause a deviation from normal operating conditions. A considerable number of such events exist, and examples can be grouped in categories:
Elevator/escalator failure Fare equipment malfunction Vandalism
At this stage of the definition process, it is only necessary to closely examine events in the first category, although the integration effort has considered all of these in the security context.
The security analysis examined many of these events in detail and produced detailed recommendations for avoiding or managing the most serious. Thorough analysis of some of these events has disclosed prospective weaknesses in maglev system concepts and implementation and has served as a guide for further integration effort.
A specific case in point is vehicle delevitation at speed. While likely to be extremely rare in operation, such events are to be avoided if at all possible. Although it is unlikely that death or injury would result from such an event, uncontrolled maximum speed delevitation could produce damage to both the guideway and vehicle.
What could produce such an unwanted event? After all, CHSST technology incorporates onboard emergency battery holdup for the levitation elements. The difficulty in these cases comes down to braking. Considerable kinetic energy must be removed and dissipated to bring the vehicle to a safe stop from maximum speed, all the while maintaining levitation power.
System-wide or local loss of wayside power (among other causes) can precipitate this event. When this occurs, vehicles at speed must immediately brake at rates that do not violate passenger safety criteria in emergency situations. This implies that all braking systems on the vehicle that can function will come into play to achieve a safe stop. Further, it must be demonstrated that levitation battery backup is sufficient to sustain levitation through this process. The Colorado 200 vehicle will have to be subjected to thorough testing prior to deployment to verify that this occurs safely and reliably at the maximum safe vehicle velocity in the Colorado system, under operating conditions within the system specifications.
Colorado Maglev Project Part 3: Comprehensive
The electrification analysis identifies the options for meeting the electric power needs of the CMP by comparing its aggregated energy needs with the existing capability of the electric utilities serving the 1-70 corridor. Other power supply options, such as distributed generation, will be evaluated if the incremental cost to the electric utility of meeting the maglev systems energy needs is excessive. Other considerations, such as reliability of service, could also be a factor in supporting alternate power supply options.
The Electrification Analysis is composed of the following sections:
1. Existing and Planned Power Supply Resources 2. Power Requirements and Supply Adequacy 3. Feasibility of Distributed Generation 4. Comparison of Electric Supply Options and Recommendations
The following sections summarize the work performed and the respective findings.
4.1. EXISTING AND PLANNED POWER SUPPLY RESOURCES This discussion identifies the existing generation, transmission, and distribution resources in Colorado with particular emphasis on resources along the corridor that could potentially supply the maglev system's electricity needs. For the purposes of this assessment, the "corridor" was . arbitrarily defined as a 16 km (10 mile) band north and south of 1-70 that straddles the proposed maglev system route. The 16 km (10 mile) distance is the range that a new sub transmission or distribution line could be realistically constructed to meet the maglev project needs. Accordingly, it is necessary to identify all the utilities, generating stations, transmission lines and substations situated within this 16 km (10-mile) north/south band along 1-70.
The major outputs include: Identifying all electric utility resources, existing and planned, along the maglev route such as transmission and distribution lines, key substations and generating stations that impact the electric supply to the maglev system; • Ownership, rated capacities and voltage of transmission and sub transmission lines and major substations along the proposed maglev corridor; • Daily and seasonal loadings on select transmission lines and relevant transmission expansion data from utilities that will potentially supply the maglev system; • Historical system outage and transmission reliability data from concerned utilities; • Existing and planned (electric) load growth of major urban areas along the route, their historical outage rates and system expansion forecasts that address the electric load growth. Results: The utilities, including municipals and cooperatives serving the maglev corridor, generating plants, transmission lines, and substations have been identified and classified according to their relevant capacities.
Additionally, power pickup points along the proposed route were identified based on the preliminary route selection. The power pickup points will be the interface between the utility and the maglev system. The conversion of the utility power to the maglev system voltage will occur downstream of the power pickup points by rectifier units located along the guideway. Sixteen such power pickup points were identified for the purpose of this study from the DIA to the Eagle County Airport. These sixteen locations were selected based on where maximum power needs
are expected along the route at a spacing of 11 to 16 km (7 to 10 miles), and at locations where a higher reliability of power supply may be indicated. These pickup points are identified and discussed in more detail in this report, although the data suggests that the largest portion of the maglev system power needs between DIA and Eagle County Airport will be handled by Public Service Company of Colorado or Xcel Energy, with a relatively smaller share by Holy Cross Electric Association.
The information collected has been graphically summarized in Figure 51, showing the existing electric utility resources including power plants, transmission and substations. In addition, Figure 51 also shows the location of the sixteen power pickup points.
4.1.1. Utilities and Service Areas The eight utilities serving the corridor were identified and are listed in Table 4.1-1 Corridor Utility Names. The table also lists the type of utility, Investor Owned (IOU), Municipal or Co-operative District. Public Service of Colorado (PSCO) is the only IOU in this set of eight utilities serving the corridor.
The areas served along the corridor are shared by the utilities identified in Table 4.1-1. In some instances, the utility might serve only a small area that is surrounded by another utility's service area. One approach to determine where such pockets or service boundaries exist is to examine each zip code in the corridor and determine which utilities serve this geographic area. This information is presented in Table 4.1-2, where each zip code includes the names of the utilities operating in this area. The third column in this table indicates the percentage of this geographic area served by each utility, designated by a "% Overlap". If the entire zip code area is served by a single utility, the value in this column is 1 and if the area is shared by two or more entities, the value in this column changes to reflect the percent area served by that utility. Where there is more than one utility serving the same zip code, the aggregate values of all the utilities serving that area equals unity. The data in this table shows that Public Service Company of Colorado serves the largest area along the corridor.
4.1.2. Power Plants The power plants within the defined corridor zone and some within very close proximity to this region were identified along with their ownership and winter capacity ratings in Megawatts. This information is presented in Table 4.1-3 where the list is sorted by increasing plant sizes. The table shows that the largest generation stations along the route are owned by PSCO in the 300 to 700 MW size range, followed by several smaller generation facilities owned by municipals as well as merchant plants.
4.1.3. Transmission Lines Data for all transmission in the voltage class of 115 kV and above was collected for the corridor. These are all existing lines, except for the 500 kV line owned by the Western Power Administration from Denver Terminal to Spence. Ownership, voltage and service area location of each existing substation of interest was identified. Generally, these are single line corridors; however, there are a few parallel circuits as shown in the “Lines" column.
4.1.4. Substations Ownership, voltage and service area location of each existing substation of interest was However, the existing loading at these substations has not been determined. Comparison of the existing substation capacity with the historic peak loading data will determine the capacity that may be available to the maglev system. This is usually a good indicator of the available substation capacity, unless the utility is aware of other developments, which could mortgage it for future use.
Colorado Maglev Project Part 3: Comprehensive Page 6
4.1.5. Power Pickup Points Sixteen locations were identified along the guideway between DIA and Eagle County Airport. These power pickup points were located where maximum power needs are expected to occur, such as at steep grades, or at locations where the route makes a significant or sharp change in direction. Their spacing varies from 11 to 16 km (7 to 10 miles). A few power pickup points were also located where there may be a greater need for reliability of power supply such as when the route crosses through the EJMT. In this case, a power pickup point is located at both ends of the tunnel providing a dual feed capability for that segment of the route.
The power pickup point locations are preliminary, although they are appropriate for conceptual design purposes. The exact geographic locations will emerge in the final design stages of the project based on how and where the utility chooses to supply the maglev system, most likely with a feeder in the 15 kV class. Conductors from this substation will feed the rectifier units located at frequent intervals along the guideway to convert the AC to the DC voltage of the maglev system.
Coordinate information was used to identify the location of these power pickup points by zip code and the utility serving that zip code as shown in Table 4.1-4. The table shows that United Power Inc. and Intermountain Rural Electric Association serve some of the locations. Both these are rural cooperatives that serve areas around DIA and small pockets West of Denver. However, Public Service of Colorado, or Xcel Energy will in fact handle construction of any substation at these locations for the maglev project due to agreements that exist between these entities. Therefore, twelve of the sixteen locations shown are under Xcel's control, the remaining four are in the Holy Cross Electric Association's service area, which means that Xcel will be the supplier handling almost all the power needs of the maglev system between DIA and Eagle County Airport.
Table 4.1-2 Zip Codes Along Corridor Shared by Utilities
Zip Code 181506 81506 81521
81630 81630 81630 81635 181635 81650 81650
% Overlap 10.677926960 0.322073152 1.000000000 11.000000000 10.997108370 10.054799559 10.597655960 0.347163250 10.154393504 10.844467888 10.100088849 0.133904000 0.533117965 0.232917848 0.733151969 0.266841215 0.011576465 10.879722652
Type ELEC-Non IOU ELEC-IOU ELEC-Non IOU ELEC-Non IOU ELEC-Non IOU ELEC-Non IOU ELEC-Non_IOU ELEC-IOU ELEC-Non_IOU ELEC-IOU ELEC-Non_IOU ELEC-Non IOU ELEC-Non_IOU ELEC-IOU ELEC-Non IOU
ELEC-IOU ELEC-Non IOU ELEC-Non IOU
Company Name Grand Valley Rural Power Lines, Inc. PSC of Colorado Grand Valley Rural Power Lines, Inc. Grand Valley Rural Power Lines, Inc. Grand Valley Rural Power Lines, Inc. Moon Lake Electric Association, Inc. Grand Valley Rural Power Lines, Inc. PSC of Colorado Holy Cross Electric Association, Inc. PSC of Colorado Moon Lake Electric Association, Inc. Holy Cross Electric Association, Inc. White River Electric Association, Inc. PSC of Colorado Holy Cross Electric Association, Inc. PSC of Colorado Glenwood Springs Electric System Holy Cross Electric Association, Inc. PSC of Colorado Sangre de Cristo Electric Association, Inc. PSC of Colorado Holy Cross Electric Association, Inc. Yampa Valley Electric Association, Inc. Mountain Parks Electric, Inc. PSC of Colorado Holy Cross Electric Association, Inc. Holy Cross Electric Association, Inc. Yampa Valley Electric Association, Inc. Holy Cross Electric Association, Inc. Holy Cross Electric Association, Inc. PSC of Colorado Holy Cross Electric Association, Inc. PSC of Colorado Yampa Valley Electric Association, Inc. Holy Cross Electric Association, Inc. Mountain Parks Electric, Inc. Mountain Parks Electric, Inc. PSC of Colorado Intermountain Rural Electric Association PSC of Colorado PSC of Colorado Intermountain Rural Electric Association
ELEC-IOU ELEC-Non_IOU EC-IOU
0.158506233 0.835579710 10.195192354 10.043442279 0.616974893 0.144416916 0.999081284
ELEC-Non IOU ELEC-Non IOU ELEC-Non IOU ELEC-IOU
1.000000000 10.068651376 0.931348524 10.355334753 0.644667602 0.812113090 0.186696626 0.617864033 0.380741990 0.992409949
ELEC-Non_IOU ELEC-Non_IOU ELEC-Non IOU ELEC-Non_IOU ELEC-Non IOU ELEC-IOU ELEC-Non IOU ELEC-IOU ELEC-Non IOU ELEC-Non_IOU ELEC-Non IOU ELEC-Non IOU ELEC-IOU
Zip Code 180433 80435 80435 80439 80439 80452 80452 80452
10.023157112 10.747724907
10.228295588 10.923352339 10.076680185
ELEC-Non IOU ELEC-Non IOU ELEC-IOU ELEC-Non IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-IOU
Company Name PSC of Colorado Holy Cross Electric Association, Inc. PSC of Colorado Intermountain Rural Electric Association PSC of Colorado Holy Cross Electric Association, Inc. Intermountain Rural Electric Association PSC of Colorado Intermountain Rural Electric Association PSC of Colorado Intermountain Rural Electric Association United Power, Inc. PSC of Colorado Intermountain Rural Electric Association PSC of Colorado PSC of Colorado PSC of Colorado PSC of Colorado PSC of Colorado PSC of Colorado PSC of Colorado PSC of Colorado PSC of Colorado PSC of Colorado PSC of Colorado PSC of Colorado Intermountain Rural Electric Association PSC of Colorado PSC of Colorado Intermountain Rural Electric Association PSC of Colorado PSC of Colorado PSC of Colorado United Power, Inc. PSC of Colorado PSC of Colorado PSC of Colorado PSC of Colorado PSC of Colorado PSC of Colorado PSC of Colorado PSC of Colorado PSC of Colorado PSC of Colorado
80226 180228 80232 80401 80401 80235 80127 80127
1.000000000 1.000000000 1.000000000 1.000000000 1.000000000 1.000000000 1.000000000 1.000000000 1.000000000 1.000000000 1.000000000 0.350284864 10.649095143 1.000000000 10.626562021 10.373437825 1.000000000 1.000000000 10.349732850 10.650267808 1.000000000 1.000000000 1.000000000 1.000000000 11.000000000 1.000000000 11.000000000 1.000000000 11.000000000
ELEC-IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-Non_IOU ELEC-IOU ELEC-IOU ELEC-Non_IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-Non_IOU ELEC-IOU ELEC-IOU ELEC-IOU
Type ELEC-IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-IOU
PSC of Colorado PSC of Colorado PSC of Colorado PSC of Colorado
% Overlap 1.000000000 1.000000000 1.000000000 1.000000000 1.000000000 1.000000000 11.000000000 1.000000000 1.000000000 1.000000000 1.000000000 1.000000000 1.000000000 1.000000000 11.000000000 1.000000000 1.000000000 1.000000000 1.000000000 1.000000000 1.000000000 1.000000000 1.000000000 1.000000000 1.000000000
ELEC-IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-Non IOU ELEC-IOU ELEC-IOU
PSC of Colorado PSC of Colorado
0.993032808 1.000000000 1.000000000 0.223263502 10.776735701 1.000000000 11.000000000
PSC of Colorado PSC of Colorado United Power, Inc. PSC of Colorado PSC of Colorado PSC of Colorado Intermountain Rural Electric Association PSC of Colorado Intermountain Rural Electric Association PSC of Colorado Intermountain Rural Electric Association PSC of Colorado PSC of Colorado PSC of Colorado PSC of Colorado United Power, Inc. PSC of Colorado
80111 80017 80011 80013 80022 80022
0.506130174 10.535738280 10.464261828 0.039538966 0.960461959 1.000000000 1.000000000 1.000000000 0.408508751 0.591491808
ELEC-IOU ELEC-Non IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-Non_IOU ELEC-IOU
80018 80019 80137 80137 80137
Company Name PSC of Colorado PSC of Colorado United Power, Inc. PSC of Colorado United Power, Inc. PSC of Colorado United Power, Inc. United Power, Inc. PSC of Colorado PSC of Colorado PSC of Colorado Intermountain Rural Electric Association United Power, Inc. PSC of Colorado Intermountain Rural Electric Association Mountain View Electric Association, Inc. United Power, Inc. Morgan County Rural Electric Association PSC of Colorado Intermountain Rural Electric Association Morgan County Rural Electric Association Intermountain Rural Electric Association Grand Valley Rural Power Lines, Inc. Grand Valley Rural Power Lines, Inc. PSC of Colorado Grand Valley Rural Power Lines, Inc. PSC of Colorado Grand Valley Rural Power Lines, Inc. PSC of Colorado Grand Valley Rural Power Lines, Inc. PSC of Colorado Grand Valley Rural Power Lines, Inc. PSC of Colorado PSC of Colorado Grand Valley Rural Power Lines, Inc. PSC of Colorado Grand Valley Rural Power Lines, Inc. PSC of Colorado Delta-Montrose Electric Association Gunnison County Electric Association, Inc. Holy Cross Electric Association, Inc. PSC of Colorado Grand Valley Rural Power Lines, Inc. PSC of Colorado
% Overlap 0.997563788 11.000000000 10.452468421 10.547530741 0.862431935 10.137568129 1.000000000 10.362998291 10.637004720 (1.000000000 1.000000000 0.026409507 10.017267194 0.956322025 0.804403943 0.068051411 10.010576074 0.027057672 0.089912479 10.995377341 10.659808432 10.340191576 10.997959750 10.220213582 0.779787735 10.568719078 0.431281138 0.551393605 10.448606850 10.977456360 10.022543419 10.441884833 10.558115347 10.999178836 10.724203595 0.273150524 10.894636992 10.103521893 10.020906920 10.068976924 10.774445689 0.134298527 10.685500029 10.309988885
Type ELEC-IOU ELEC-IOU ELEC-Non IOU ELEC-IOU ELEC-Non IOU ELEC-IOU ELEC-Non IOU ELEC-Non IOU ELEC-IOU ELEC-IOU ELEC-IOU ELEC-Non_IOU ELEC-Non_IOU ELEC-IOU ELEC-Non IOU ELEC-Non IOU ELEC-Non IOU ELEC-Non_IOU ELEC-IOU ELEC-Non IOU ELEC-Non IOU ELEC-Non IOU ELEC-Non IOU ELEC-Non_IOU ELEC-IOU ELEC-Non IOU ELEC-IOU ELEC-Non_IOU ELEC-IOU ELEC-Non IOU ELEC-IOU ELEC-Non IOU ELEC-IOU ELEC-IOU ELEC-Non IOU ELEC-IOU ELEC-Non IOU ELEC-IOU ELEC-Non IOU ELEC-Non IOU ELEC-Non IOU ELEC-IOU ELEC-Non IOU ELEC-IOU
81501 81501 81503 81503 81504 81504
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Table 4.1-3 Generating Stations, Ownership and Winter Capacity Ratings (MW)
Capacity Plant Name Operator Name Company Name (MW) Foothills Hydro Plant Denver Water Dept. Denver, City & County of 10.91 Hillcrest Power Plant Denver Water Dept. Denver, City & County of 11.10 Dillon Hydro Plant Denver Water Dept. Denver, City & County of 11.81 Peach Queen Powerstation Hydro-West of Colorado Hydro-West of Colorado 2.50 Colorado Landfill Gas Gen. Proj. Energy Developments, Ltd. Energy Developments, Ltd. 14.80 Metro Wastewater Coger Trigen-Colorado Energy Corp. Trigen-Colorado Energy Corp. 5.00 Metro Wastewater Cogen Trigen-Colorado Energy Corp. Denver Metrop. Wastewater Reclam. Dist. 5.00 PDH Cogeneration Project PDH Energy Partnership, Ltd. PDH Energy Partnership, Ltd. 6.50 Gross Hydro Plant Denver, City & County of Denver, City & County of 17.88 Denver Metro. Wastewater Metropolitan Waste Water Reclamation Metro Wastewater Reclam. D Reclam. District 19.80 American Gypsum Cogen. National Energy Systems Co. National Energy Systems Co. 19.84 Shoshone (PSCO) PSC of Colorado PSC of Colorado 15.00 Golden Plant Trigen Nations Energy Co. Trigen-Colorado Energy Corp. 17.70 Golden Plant Trigen Nations Energy Co. Nations Energy Corp. 17.70 Fruita PSC of Colorado PSC of Colorado 20.00 Total Petroleum PSC of Colorado PSC of Colorado 23.00 Glenwood Springs Salt Project Glenwood Springs Salt Co., L.P. Glenwood Springs Salt Co., L.P. 34.00 Rifle Generating Station Tri-State G&T Association, Inc. Tri-State Generation & Transmissions 185.00 Zuni PSC of Colorado PSC of Colorado 107.00 PG&E National Energy Group, Plains End linc. PG&E National Energy Group, Inc. 1111.00 DIA Power Project North American Power Group North American Power Group 150.00 Arapahoe (Blhige) Black Hills Generation, Inc. Black Hills Generation, Inc. 193.00 Cabin Creek (PSCO) PSC of Colorado PSC of Colorado 324.00 Blue Spruce Energy Center SkyGen Services SkyGen Services 338.00 Cameo PSC of Colorado PSC of Colorado 430.70 Arapahoe (PSCO) PSC of Colorado PSC of Colorado 472.00 Cherokee (PSCO) PSC of Colorado PSC of Colorado 728.50
Colorado Maglev Project Part 3: Comprehensive Page 8
calculated for each discrete segment moving west from a point near the DIA with assumed headwinds of 0, 25, 45 and 90 kph. The MathCAD data set was imported into an Excel spreadsheet to identify the segment where peak power demand occurs and to identify the segments leading into and away from the peak segment, assuming a westerly direction of travel. This provides a clear picture of the location where the peak demand occurs and the grade of the guideway at this location and the adjacent locations.
According to this analysis, the peak demand will be 2,320.12 kW per car, or 4,640.24 kW for each 2-car train. This demand occurs at a 7.48% grade at a distance of 171.85 km (segment 1551) west of DIA on the eastbound track with a 90 kph headwind. Similarly, the peak in the westbound direction will be 2,098.05 kW per car, or 4,0196.10 kW per train and occurs at a 6.59% grade at a distance of 124.45 km (segment 1111) west of DIA under 90 kph headwind conditions. The steeper grades in the route excursions from 1-70 are estimated to be on the order of 10% to 12% with grade lengths possibly on the order of a few miles. Such lengths will be sufficient to establish steady speed operation following a transient slowdown from higher speed on a down hill or level section. Given that the motor was designed for maintenance of 160 kph speed on grades up to 7%, at greater grades, the motor will operate at maximum power to achieve the highest speed possible that the grade and wind load will permit, within the limits of the route curvature. At the 12% grade, the peak power demand per car would be 1.7 times the maximum of 2.3 MW per car addressed on the 1-70 route at the average speed. This level may well fall within the sizing of the substation when the power available from the local battery system (for storage of regenerated power when braking) is considered. The length of the high-grade sections are very short compared to the entire route length, and offset by the stored, regenerated power from braking, the impact of the additional electrical energy demand is expected to be small.
For purposes of electric supply planning, the maglev corridor is divided into segments of 11 to 16 km lengths as described in the analysis. These are the power pickup points where the 25 kV AC supply grid interfaces with the rectifiers supplying the DC traction power. The power consumption of the maglev system determines the size of the transformers designed for these power pickup points or substations. The current assumptions of peak ridership and headway clearance indicates that there could be no more than two trains in each direction of travel or four trains in both directions between two adjacent substations. Thus the substation load for the train traction power would be no more than four times or (4,640.24 x 4) kW = 18,560.96 kW, or a nominal load of 20 MW at each substation.
The number of active trains on the track for the same ridership assumptions indicates that there are a total of 44 (2-car consist) trains in the corridor. The peak load of each eastbound train of 4,640.24 kW, computed above is used to compute the total traction load for the entire corridor, assuming that all 44 trains are operating on the guideway. This load is (4,640.24 x 44) kW = 204,170.56 kW or 205 MW, nominal.
Similarly, the energy required for the traction power of each train is also computed from the MathCAD/Excel data set for headwinds of 0, 25, 45 and 90 kph. The 0 kph headwind yields the lowest energy consumption due to the absence of drag; the higher headwind conditions yield correspondingly higher consumptions. The energy requirements calculated in the spreadsheet include the reduction from regenerative braking accumulated over the entire route in each direction. The analysis indicates that the eastbound trains require less energy traveling from Eagle to DIA due to the lower elevation of the Denver region by approximately 350 meters. The eastbound train energy consumption benefits both from the decreasing elevations in the easterly direction and the cumulative effects of regenerative braking.
The four headwind assumptions yield both a worst- and best-case estimate of energy consumption bracketed by the 0 and 90 kph envelopes. The worst-case energy estimate is obtained from the 90 kph condition for all westbound trains. Since it is assumed that the peak traffic is 44 trains, then 22 trains would be heading west with 90 kph headwinds, and 22 trains
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heading east under a tailwind condition of 90 kph. For the purpose of this analysis, tailwind conditions are assumed to make no contribution, and are treated the same as a 0 kph headwind. Therefore, the westbound trains require (1,225.29 kWh x 22) = 26,962.98 kWh, and the east bound require (682.41 kWh x 22) = 15,013.02 kWh, or a total of 41,976 kWh or approximately 42 MWh,
The more likely average wind conditions on an annual basis for the entire route are assumed to lie between the 25 kph and 45 kph conditions. This results in energy requirements of (884.30 kWh x 22) = 19,454.60 kWh for westbound trains with 25 kph headwind and (844.50 kWh x 22) = 18,579.00 kWh for the eastbound trains with 45 kph headwind. The total energy requirements for this scenario are 38,033.60 kWh or 39 MWh.
The best-case scenario would be 0 kph headwind for both direction of travel which is (795.23 kWh x 22) = 17,495.06 kWh, westbound and (682.41 kWh x 22) = 15,013.02 kWh, eastbound, for a total energy requirement of 32,508.08 kWh or 33 MWh.
Examining the best- and worst-case energy requirements and considering the likely case requirement of 39 MWh, it is estimated that the average consumption is in the 37 MWh to 39 MWh range.
These power and energy requirements are summarized below:
Maximum power required per car Maximum power required per train Maximum power needed at each substation Total guideway electric load w/44 trains Estimated guideway electric energy w/44 trains
2,320.12 kW (on eastbound leg)
4.2.2. Substation Design With four trains between adjacent substations, it was determined that each substation could have a peak load of 20 MW. Based on this load, a 25 MVA transformer is selected for each substation, which is approximately 5 MVA larger than the estimated traction load of the trains. The higher rating allows for some margin in the power requirement estimates and accommodates ancillary loads such as station power, communication and control loads. This margin offers operational flexibility and accommodates higher train traffic patterns or off normal operations due to unforeseen conditions as well. Therefore, a standard substation layout, with two 25 MVA transformer banks at each substation is proposed for the maglev system. This substation configuration allows for a high degree of reliability, ease of maintenance and accommodates future growth in the maglev train system.
The conceptual substation layout with two transformer banks is shown in Figure 52. Both Transformer Banks 1 and 2 step down the AC grid voltage from 115 kV to 25 kV, and have a 25 MVA rating, each. Bank 1 is the primary transformer supplying two 25 kV feeders, 1A and 1B, that route the power to the rectifier section that converts the AC to the 3 kV DC required by the maglev system. Transformer Bank 2 is in a standby mode and is used when substation service is required to repair switchgear or other equipment or, if the future train traffic patterns change and more than four trains are operated in each segment. This redundancy provides a higher degree of maintainability and reliability while accommodating future growth and not locking the guideway into an operation mode restricted by transformer capacity. This redundant design is common utility practice and assures a greater degree of flexibility for a nominal increase in the capital cost of the project. Feeder 1A and 18 feed the rectifier section for traction power as shown in Figure 53. The rectifiers convert the 25 kV AC to the 3,000 V DC required for the maglev system.
Colorado Maglev Project Part 3: Comprehensive
The substations also have a dual feed from the 115 kV transmission grid shown by the two taps feeding the substation. These two feeds originate from two separate transmission substations one in the east, perhaps at Dillon, and one in the west, in or near Denver. The maglev system substation breakers are configured to draw power from either source to feed the 25 MVA transformer banks. This configuration extends the reliability deeper into the grid, thus assuring that the substations; hence the guideway has as reliable a power source as is operationally possible.
4.2.3. Station Power Most of the train stations are assumed to be at the higher elevation of the guideway and will require elevators or escalators for passenger use. Additionally, all the stations will have winter heating requirements. Thus, the station load, including lighting will be 50 kW. Additionally, each station is assumed to have a combination pneumatic and electric track switching capability to move the cars between tracks. This load is assumed to be approximately 150 kW. Thus, the total station load is 200 kW, and is supplied by a dedicated 200 KVA/480 V transformer shown in Figure 53.
4.2.4. Onboard Auxiliary Power An allowance is made for on-board auxiliary power of 200 kVA at 13.8 kV to accommodate heating and other loads within the train. A dedicated 200 kVA/13.8 kV transformer is shown for this use in Figure 53.
4.2.5.1. Base Case At the inception of this work, the approach proposed for supplying power to the maglev system was to build power pickup points or substations at 11 to 16 km intervals along the guideway. Each substation would be supplied with a 115 kV or a 25 kV feed where possible. These substations would in turn supply the rectifiers that supplied the guideway with the required 3 kV DC. Upon examining the existing substation capacities near the proposed guideway and consultations with Holy Cross Electric Association, it was clear that the power needs of the maglev system would not be met with the existing substation capacity. Hence each substation would need its dedicated feed from the 115 kV grid directly. Hence the "base option" was to build approximately 25 substations along the guideway, each with a nominal 50 MVA capacity distributed in two 25 MVA transformer banks.
A major drawback to this approach emerged as further work was performed and following discussions with the region's electric utilities regarding the practical implementation of the magiev project's electric infrastructure. The most constraining drawback was the issue of right-of-way and the related permitting to secure the 115 KV feed to each substation. Under this scenario, each substation would require negotiating a separate ROW and permit to provide the 115 kV feed from the transmission corridor. The process of securing the ROW and the permitting process for the new transmission paths, even if each were a few miles long, would introduce a high degree of uncertainty in building each substation. The process would have to be repeated for each of the 25 substations; in other words, each new line to the 25 subs would be treated as an individual project
Colorado Maglev Project Part 3: Comprehensve
4.2.5.2. Alternate Option The alternate option that emerged as a more feasible approach was to build a 115 kV transmission circuit within the right-of-way of the maglev corridor. The substations would still be 11 to 16 km apart as originally proposed, although they would tap into the 115 kV line, which would be within the guideway's corridor. Using this approach avoids building 25 separate feeds to each of the substations from the 115 kV grid. However, this option restricts the 115 kV line to be buried and designed as an underground transmission line. Safety of operation of the maglev system and the need to minimize public opposition to a new overhead transmission corridor is the forcing function for the underground option.
From a safety perspective, exposed 115 kV conductors suspended from the guideway are not a desirable or practical design option. Further, the catenaries formed by the suspended cable raises issues of ground clearance and clearance from the guideway to operate safely. Thus, an underground option might appear to be the only feasible design choice.
Based on current cable specifications used by Holy Cross Electric, this 115 kV circuit can support over 112 to 120 km of the maglev system's load, before experiencing a 5% voltage drop. This distance is also a convenient midpoint of the approximately 240 km of the proposed guideway length. It is expected that a transmission tap at Denver and another at an intermediate location, such as Dillon should be able to meet all of the maglev systems power needs. The two taps are shown in Figure 51.
A related advantage of building a 115 kV path in the guideway corridor is that it opens up a new transmission path that could be attractive to Xcel and Holy Cross Electric. Both utilities have constraints in building new transmission lines due to public opposition to new corridors. However, a transmission path that is not visible and serves a dual community purpose would be far less likely to draw public opposition and would be inherently more attractive to both the users and the regional suppliers of electricity.
A significant disadvantage of this approach is that the adverse terrain/soil conditions could make it infeasible to bury the cable in the maglev system ROW in some locations. In these instances, the guideway design would have to be altered to accommodate some alternate form of power carrying capability. A second disadvantage is to increase the overall cost of the electric supply infrastructure. It is estimated that a buried 115 kV transmission line would add $2 million per mile to the cost of the electric infrastructure. This would be in addition to the $2 million for each substation. Fortunately, newer technology, in the form of the gas insulated transmission line, provides another feasible alternative for construction of the needed transmission circuit.
4.3. FEASIBILITY OF DISTRIBUTED GENERATION
4.3.1. Background The original work plan for the Electrification task of the CMP specified a study of the Feasibility of Distributed Generation. At the inception of the Electrification effort, the expectation was that the maglev system would be powered by a network of substations individually supplied by 25 kV feeders from existing substations in the corridor vicinity. The information gathered in the Existing and Planned Power Supply Resources, indicated several constraints to this approach, which led to proposing a 230 kV underground transmission corridor parallel to the maglev right of way. This change led to some changes in the scope of this work effort. Specifically, the need to identify natural gas availability and pricing does not necessarily apply to the overall project.
4.3.2. Typical Substation Design and Cost In the earlier discussion it was noted that the 4 trains between adjacent substations generates a peak load of 20 MW at each substation. Based on this estimate, a 25 MVA transformer and associated breakers were selected as the baseline requirement for each substation. (The 25
Page 9
MVA rating includes a 5 MVA margin for any unexpected design contingencies). Therefore, a standard substation layout, with two 25 MVA transformer banks at each substation is proposed for the maglev system.
The conceptual substation layout with two transformer banks is shown in Figure 52 above. Both Transformer Banks 1 and 2 step down the AC grid voltage from 115 kV to 25 kV, and have a 25 MVA rating, each. Bank 1 is the primary transformer supplying two 25 kV feeders, 1A and 1B, that route the power to the rectifier section that converts the AC to the 3 kV DC required by the maglev system. Transformer Bank 2 is in a standby mode and is used when substation service is required to repair switchgear or other equipment or, if the future train traffic patterns change and more than four trains are operated in each segment. This redundancy provides a higher degree of maintainability and reliability while accommodating future growth and not locking the guideway into an operation mode (train schedule) restricted by transformer capacity. This redundant design is common utility practice and assures a greater degree of flexibility for a nominal increase in the capital cost of the project.
The substations also have a dual feed from the 115 kV transmission grid shown by the two taps feeding the substation. These two feeds originate from two separate transmission substations – one in the west, perhaps at Dillon, and one in the east, in or near Denver. The maglev system substation breakers are configured to draw power from either source to feed the 25 MVA transformer banks. This configuration extends the reliability deeper into the grid, thus assuring that the substations, and further the guideway, have as reliable a power source as is operationally possible.
4.3.3. Substation Costs The conceptual design of the 25 MVA maglev systems substations was used to obtain cost information from utility distribution engineers both in Colorado and New Mexico. The dual information approach was used to bracket the estimated cost of the substations because of wide variations in substation design practice among utilities. Given the same substation design, different utilities specify a wide range of breakers dictated by their protection and interconnection guidelines. Obtaining cost information from the two sources captures this cost variability and provides a higher confidence level in the estimated costs. Tables 4.3-1 and 4.3-2 show the costs obtained from Colorado and New Mexico, respectively.
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The two tables highlight the differences in substation design approaches at the two utilities. The Colorado utility builds 25 MVA, 115 kV substations and had a more refined cost estimate including site-specific cost components such as engineering, survey and soils study. The New Mexico utility chose to cost out 230 kV substations, which closely matches the maglev system requirements, with the exception that their primary cost driver is the breaker configuration that requires seven breakers which yields a double breaker double bus configuration. That cost is shown in the upper part of Table 4.3-2, and a "reconfigured” substation cost utilizing only three breakers (more representative of the standard maglev system substation) is shown in the lower portion.
Both tables show single site and multiple site costs since utilities build only one or two substations at a time. In the maglev project there could be as many as 30 such substations, which clearly indicates the potential for cost savings due to volume purchase of equipment as well as an overall reduction in repetitive site specific costs such as site engineering. The single unit costs of both tables reflect an assumed reduction due to volume procurement of the major components such as transformers and switchgear as well as a reduction of site specific costs.
Normalizing the assumptions of the two substations indicates the single site cost for each maglev system substation to be between $2,375,000 and $2,641,515, through capture of volume discounts.
4.3.4. Energy Storage Systems An energy storage system is needed to provide the levitation and motive power energy needs if there is an outage of electric power from the commercial sources. The maglev system braking time and distance calculations provide the stopping time estimates for a 7% downhill grade with normal and 10% overcurrent to the LIMs as 51 seconds and 38 seconds', respectively. Maximum power draw calculations from the Electrification analysis show that each train draws 4,640 kW. Since there could be as many as two trains in each segment, the power requirement is 5,280 kW. Using the longest braking time of 51 seconds gives a gross energy of 131 kWh produced by the train in a regenerative braking mode. An energy storage system is needed to
Braking Distance and Time on Grade calculations made for Propulsion Trade Study, November 30, 2003.
Colorado Maglev Project Part 3: Comprehensive absorb the regenerative braking as well as providing the levitation energy to bring the train to a complete stop. 4.4.3. Gas Insulated Transmission
Battery storage systems have been designed and built to support rail systems with the objective of storing the regenerative braking energy and applying it to traction energy as the trains accelerate. The San Diego regional transit system experimented with a 400 kW battery system in the early 1990's. However, this and other systems have full function dc-to-ac inverters, which, in the case of the maglev system could be eliminated with substantial cost benefits. The power conversion system (PCS) in almost all large battery systems constitutes 25% to 30% of installed costs. In the case of the maglev system, the power requirements are greater than the energy requirements that tend to shift the major cost component to the PCS. Eliminating the PCS and keeping the energy storage system entirely DC could reduce the cost of the energy storage systems significantly.
The battery system conceptualized for the maglev system could "float" at the traction voltage of 3,000 Vdc with a storage capacity of approximately 160 kWh, thus eliminating the need for a PCS. The battery would regulate at the track voltage and remain at an average 80% state-ofcharge, thus maintaining the capability to absorb the regenerative braking energy during normal operation mode. During the emergency operation mode when there is loss of utility power, the battery would still absorb most of the regenerative braking and also provide levitation power as the train slows to a complete stop.
A battery system with the appropriate charging and control subsystems to meet this requirement would cost approximately $1,100/kWh, with a total cost of $176,000 per system. There are four segments in the maglev system corridor where the grades are in the 7% range, and it is proposed that one such battery system be provided in each of the four segments.
Other storage technologies such as flywheels or superconducting magnetic energy storage could also meet these functional requirements and may have some technical advantage over the conventional lead-acid battery systems. However, there is not as much operating experience with these technologies at this time. It is pertinent to note, though, that the California Energy Commission announced the selection of a flywheel storage system for a regional train application on December 8, 2003. The flywheel system will capture regenerative braking energy and use it to offset commercial energy consumption of the train system. A mature demonstration of the flywheel system could be valuable in assessing its suitability for future maglev system applications.
The technical advantage of the flywheel over a battery system is that it overcomes some of the battery cycle life restrictions and the flywheel acts as a more effective energy buffer in absorbing and discharging the regenerative braking from the train while retaining the rapid charge/discharge response characteristics of the battery. However, at the needed capacities, the battery system is likely to be much more cost effective. There are now battery systems in the 40 MW/20 minute storage capacities in utility frequency regulation applications in Berlin and Puerto Rico and a new one was just installed in Fairbanks, Alaska. The increasing commercial use of these subsystems will reduce their costs further in the near future.
4.4. COMPARISON OF ELECTRIC SUPPLY OPTIONS AND RECOMMENDATIONS
4.4.1. Background The objective of this Electrification section is the development of a "preferred" option for powering the maglev system. Accordingly, this section summarizes the information gathered and the various cost and performance estimates for the electric supply system. It also traces the significant evolution in the conceptual approach that was proposed in the original work plan for this section and the one followed in the implementation.
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The concept at the inception of the Electrification effort was to power the maglev system through a network of substations individually supplied by 25 kV feeders from existing substations. The information gathered in the Existing and Planned Power Supply Resources section and discussions with area utilities made it clear that providing power to the 25 to 30 maglev system substations from existing utility-owned substations was not a viable option. The constraints included a shortage of spare capacity in the utility-owned substations as well as the difficulty in procuring the right-of-way (ROW) for each feeder to the maglev system substations.
4.4.2. Development of the Transmission Option The latter constraint of acquiring the needed ROW became the most restrictive and led to a reevaluation of the original proposed electrification approach. Absent the availability of individual feeders to the maglev system substations from existing installations, the only other feasible option was consideration of a new 115 kV transmission line parallel to the maglev corridor. proximity of such a transmission line would eliminate the ROW for new 25 KV feeders from existing facilities that are generally several miles from the maglev system substations.
Primarily, this approach guarantees a reliable and stiff electric supply system that is dedicated to the maglev system's use and eliminates the other sub-transmission paths that the power supply would include if the substations were tied to existing substations. If these paths were used, their reliability would determine the reliability of supply to that particular substation being served. And reliability statistics for the electric grid show that outages are more frequent in the subtransmission and distribution systems than in the primary transmission system. Therefore, eliminating a supply path that could include one or more substations upstream of the maglev system substation reduces the probability of an outage.
The other related advantage is that this transmission corridor can be shared by the area utilities. In the current regulatory and economic environment, electric utilities are finding it increasingly difficult to license and build new transmission paths. This region of Colorado is no exception to this national trend and a new, shared access transmission corridor with sufficient capacity to meet the maglev system needs and transmit additional power for use by the utilities in this region could be a valuable resource.
This aspect of the transmission proposal was discussed with the Colorado Public Utilities Commission's (CPUC) Section Chief of Fixed Utilities and Engineering Staff on October 6, 2003. The electric power needs of the maglev system were reviewed during this meeting and the rationale for proposing a new, shared transmission corridor was discussed. The CPUC staff agreed that a shared line would offer distinct benefits by opening up a new transmission pathway in the central region of the State. However, in order to carry sufficient power capacity that could be shared with utilities, the CPUC staff suggested increasing the voltage from 115 kV to 230 kV. This would allow additional capacity of 200 MW to 300 MW beyond the 200 MW baseline need of the maglev system that would be a sufficiently large capacity margin to be of value and interest to the area utilities.
Implementing a new transmission corridor with conventional overhead lines is an impractical proposition, especially near environmentally sensitive communities in the State unless it is made virtually invisible by fully integrating it into the design of the guideway. Passenger safety and operational reliability considerations precluded this option with a bare conductor. However, an insulated transmission system that is structurally integrated into the guideway design such that it meets safety requirements does not have the visual impact of an overhead line. This approach would likely obtain public and regulatory approval.
It should be further noted that CDOT generally has a policy excluding electric transmission facilities from highway right-of-way. A transmission facility design that could potentially be exempted from this policy is the gas insulated transmission line.
The solution that emerged as most feasible and technically compatible was the use of a gasinsulated transmission system, specifically, the Gas-Insulated Transmission Line (GIL) made by Siemens, and also by CGIT Westboro (http://www.cgit-westboro.com/). The Siemens GIL is basically a system of three gas-filled pipes, one for each phase of the transmission line. A threephase transmission system based on the GIL consists of three 500mm – 650mm diameter tubes is shown in Figure 54 below, one for each phase. The outer tube of each phase consists of the phase conductor, again a tube that is surrounded by a high insulation gas mixture.
Rated voltage up to 800 kV Rated lightning impulse withstand voltage up to 1550 kV Rated current up to 6300 A Transmission capacity 500-3000 MW Rated short-time current / duration 63 KA/3s Insulating gas N_/SFG gas mixture System length up to 100 km
Figure 55 illustrates the main components of the GIL system. These consist of a steel (or aluminum) outer enclosure (1) and a concentric inner tube made from a high-strength extruded aluminum alloy (2) that forms the main conducting element for each phase of the three-phase transmission system. The outer tube assembly is filled with an 80/20 mixture of N2 and SF6 gas to insulate the inner tube and electrically isolate the outer tube. The inner tube is mechanically supported by pairs of insulators (5) made of epoxy cast-resin and arranged 12m apart at an obtuse angle. These are fixed to the inner tube although they slide on the inside of the outer tube to compensate for thermal expansion of the conductor and enclosure tubes. The tube sections are isolated in approximately 300m sections by a conical epoxy cast-resin insulator (4) such that the pipe sections are compartmentalized and a failure in the outer tube in any section prevents the release of all the insulating gas. Adjacent inner tubes make electrical contact through sliding contacts using silver-plated surfaces and fittings (3a, 3b).
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The Siemens GIL is a modular system with sections that allows the transmission system to follow any grade or contour. Similarly, fittings allow taps to be made easily in the GIL to connect with any part of the electric grid.
4.4.4. GIL in Maglev Application Proper integration of the steel outer tube into the guideway structure allows the GIL sections to be structurally self-supporting without need for further reinforcement. In the maglev system application, it is proposed that the steel enclosed GIL tubes be mounted in between the east/west guideways in a triangular configuration, as shown in Figure 56. The metal grating above the three GIL tubes serves as a passenger emergency exit path.
As visualized conceptually in Figure 56, the GIL can be one continuous pipe system running in between the guideways. The electrical characteristics of the GIL are such that it lends itself very well to such a continuous run over long distances, without the need for any special vaults or terminations.
Figure 56 is only a conceptual representation and its implementation will require detailed design of the structure supporting the GIL and its attachment to the guideway and related design detail.
GIL costs are likely to be competitive with conventional overhead transmission installations, particularly when it is noted that GIL does not need any active compensation for lengths up to 200+ km. The electrical superiority of this approach cannot be overemphasized, since the need to generate increasing amounts of reactive power has placed a burden on many utilities, and has contributed to recent significant electric power failures in the eastern United States.
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5.0 GREENHOUSE GAS IMPACT
The objective of the Greenhouse Gas Impact analysis is to describe the regional environmental effects of developing a maglev mass transit system along the 1-70 corridor west of Denver, Colorado. Environmental effects are measured in the combination of reductions in emissions due to decreased vehicle traffic on 1-70, and increases in emissions from additional electric power sources needed to operate the maglev system. For the System Greenhouse Gas and Environmental Impact Analysis, emissions will be defined as CO2 emissions from cars and light trucks (including pickups, vans, minivans, and SUVs) and CO2 emissions from electric power sources for the maglev system. Other emissions (hydrocarbons, CO, NOX) are noted but not compared for vehicles and electric power sources.
This analysis first provides estimates of reductions in emissions from reduced 1-70 traffic. Analysis of the potential increases in greenhouse gas emissions from added electric power sources is then addressed. Finally the net greenhouse gas impact of the maglev system is calculated.
The estimates developed in this analysis are first-order estimates, based on average values for the parameters used.
5.1.1. Greenhouse Emissions from Vehicles Emissions of CO2 have been rising in all sectors of the U.S., with transportation the fastest growing sector. In 2000, transportation contributed approximately one third of national CO2 emissions. Given concerns worldwide about the global heating potential of CO2 in the atmosphere, an added potential benefit of transit systems is the reduction of greenhouse gas emissions from less automobile traffic.
Development of a maglev system in the 1-70 corridor would reduce CO2 emissions from vehicle traffic as vehicles of individuals selecting the system are driven less miles per day. Emission reductions will depend on several factors, including the proportion of 1-70 passengers that divert from vehicles to trains, the resultant reduction in miles driven by train riders, and the mix of vehicles that are diverted from the highway system. The parameters used to estimate reduced CO2 emissions are listed in the following section.
5.1.1.1. Vehicle Emission Estimation Approach The methodology used to estimate reductions in CO2 emissions from reduced vehicle use as passengers shift to the maglev system is shown in Figure 57 below. A baseline estimate has been developed using information obtained from the Colorado Department of Transportation (CDOT), the U.S. Department of Transportation (USDOT), the Federal Highway Administration (FHA), and the U.S. Environmental Protection Agency (USEPA). Once the baseline was established, some baseline parameters were varied to determine the impacts of these changes on annual emission reductions. For example, the proportion of 1-70 corridor passenger trips diverted to the maglev system was varied, since the proportion may vary depending on eventual convenience and trip cost on the maglev system.
2 U.S. Department of Transportation, Federal Highway Administration, Air Quality Fact Book.
Figure 57: Methodology to Estimate Reductions in Vehicle CO2 Emissions
This approach does not estimate annual mileage reductions for the 1-70 corridor directly. Instead, reduction in annual mileage driven is based upon an estimated average reduction in mileage based on national traffic patterns for rail and non-rail passengers.
5.1.1.1.1. Information for Vehicle Baseline Emissions Estimate The baseline parameters for the analysis of reduction in vehicle emissions are listed in the following table.
Table 5.1-1 Parameter Values for Baseline Estimate
Number of transit trips per day Average passengers per vehicle Average car mileage per year Car CO2 emissions per mile Average light truck mileage per year Light truck CO2 emissions per mile Reduction in vehicle miles for maglev rail system users Proportion of cars in vehicle fleet
22,000 each direction 2.6 13,750 0.8 lb. 16,100 1.2 lb. 50% 65%
The baseline parameters were used to develop the initial baseline estimate of annual CO2 emission reductions due to less vehicle miles traveled. As noted earlier, since the values of the parameters are average values without ranges, the baseline estimate is a first-order estimate. The values listed for number of trips per day, percent highway trips diverted to the maglev system, and average passengers per vehicle are CMP team estimates. Average mileage and CO2 emissions for cars and light trucks were taken from the U.S. Environmental Protection Agency (EPA). The mileage values were adjusted upward by 10 percent for cars and 15 percent for light trucks to reflect higher annual mileage estimates by the U.S. Department of Transportation Bureau of Transportation Statistics (DOT BTS) for the National Transportation
Analysis Region (NTAR) 157, which includes all of Colorado, portions of southeastern Wyoming and western Nebraska. A map of the NTARs is shown in Figure 58. The reduction in vehicle miles and the proportion of cars in the vehicle fleet were derived from information in the USDOT BTS reports listed in the reference section.
5.1.2. Baseline Emissions Estimate The baseline estimate for reduction in vehicle CO2 emissions was developed in three steps: • Estimate reduction in vehicles per day because of diversion to the maglev system; • Calculate the decrease in annual miles driven by those using the maglev system; • Determine the estimated annual reduction in CO2 emissions because of decreased vehicle miles driven.
5.1.2.1. Reduction in Vehicles The estimated reduction in vehicles from the highway system as passengers divert to the maglev system is calculated as:
VR = (NR / Day)/(NP/Vehicle)
VR= Vehicle reductions per day
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NR = Number of riders diverted to the maglev system per day
VR= 22000/2.9 = 8462 8500 vehicles/day.
The reduction in vehicles will result in less miles driven, although it will not eliminate all miles for those vehicles. Local trips, trips to other communities not on the maglev line, and vacation trips will still require use of the diverted vehicles.
5.1.2.2. Decrease in Annual Miles Driven The annual reduction in miles driven is calculated as:
MR, = (P:)(PMR XV.M/ Year)
MR; = reduction in annual miles per year for vehicles replaced with maglev system rides, where i denotes either cars (C) or light trucks (LT) Pi= proportion of vehicles that are cars (C) or light trucks (LT) PMR = proportion of annual miles per vehicle reduced due to maglev system ridership VR = Vehicle reductions per dayM/Year = average annual miles driven by either cars (C) or light trucks (LT) in the region
5.1.2.3. Annual Reduction in Vehicle CO2 Emissions The total reduction in annual greenhouse gas emissions from cars and light trucks is estimated as
ER = (38,000,000)(0.8) + (24,000,000)(1.2) = 59,200,000 lbs, or 26,853 -27,000 metric tons ~ annually. Estimated Colorado CO2 emissions from all transportation fossil fuel use were about 13.7 million metric tons in 2000.
5.1.2.4. Results of Varying Parameters The parameters that are most likely to vary from the baseline values when estimating greenhouse gas reductions due to the implementation of a maglev system in the 1-70 corridor are the number of passenger trips per day, percent of passenger trips diverted to the system, and percent
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reduction in annual vehicle miles driven for train riders. Each of the three parameters was varied by †10 percent to determine changes from the baseline estimate. The results are summarized in Table 5.1-2. Table 5.1-2 Results from Varying Parameters (In Metric Tons of CO2Year)
Passenger trips Percent trips diverted Percent miles reduction
Range of Emission Reductions High Low 29,400 24,000 35,900 17,500 32,200 21,500
These results suggest that, under this estimation approach, the percent of trips diverted to the maglev system and the proportion of reduced miles driven annually by system riders have more impact on the estimated reduced CO2 emissions than variations in the total passenger trips on the system. Additional information and ranges of values for these parameters would help refine the current estimates.
5.1.3. Greenhouse Gas Emissions from Power Requirements Development of a maglev system along 1-70 would require additions to the electric power supply currently available along the corridor. The location and type(s) of power plant to supply the added electric power have not yet been specified. As a result, the approach to estimating increased greenhouse gas emissions is based on an estimate of the energy requirement per train passenger. This approach does not address the power requirements and power plant fuel mix that would be associated with power supplies from the existing power grid compared to a dedicated distributed power system for the maglev system. Additional electric power is assumed to be provided by natural gas based facilities, with an associated increase in CO2 emissions.
The level of increased CO2 emissions from added electric power requirements are a function of several factors, including energy requirements for the trains, number of passengers, travel distance, average train speed, and power plant efficiencies.
5.1.3.1. Power Requirements Emission Estimation Approach The methodology used to estimate increases in CO2 emissions from added power needs for the maglev system is shown in Figure 59. The estimate has been developed based on information from CDOT, USEPA, and the U.S. Department of Energy (USDOE). Some of the parameters used to develop the CO2 emissions estimate were varied to determine the sensitivity of the initial estimate to changes in the parameters.
This emissions estimation approach does not calculate the additional number and type of electric power facilities required. Instead, power requirements and associated emissions increases are estimated on the maglev system energy requirements per passenger. This is similar to the approach used to estimate reductions in annual vehicle emissions from reduced vehicle use, where reductions in emissions were based on the number of passengers diverted to the maglev system from 1-70 and typical driving patterns, rather than estimated annual mileage reductions. The increased emissions estimate is also a first-order estimate, based on average values for the parameters used.
Donald M. Rote, Guidelines for Estimating Trip Times, Energy Use and emissions for HSGT Technologies, Section 3.
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5.1.3.2. Information for Power Requirements Emission Estimation Approach The values of the parameters used to estimate increases in greenhouse gas emissions from additional power for the maglev system are listed in Table 5.1-3.
Table 5.1-3 Parameter Values for Increased Emissions Estimate
PARAMETER INITIAL VALUE Energy required per train car 750 kW Average number of passengers per train car 100 Rail line length 244 Kilometers Average train speed 138 kilometers/hr Total passenger trips 22000/day each way Average distance traveled 150 kilometers Energy/ft. natural gas 1025 Btu/ft.3 Power plant efficiency? 30%-50% CO2 emissions 3.19 x 10-5 lbs/Btu 1 Initial value for average distance traveled is based on 50% of passengers traveling the full length of the rail system from DIA, and 50% traveling to/from Golden and DIA, 55 kilometers. Efficiency ranges are for NG turbines and larger NG combined cycle facilities.
The information for energy per train car and average passenger load was taken from earlier CMP analysis. Maglev system length and average speed are CDOT estimates, total passenger trips, and average-distance-traveled are CDOT team estimates. Natural gas (NG) energy per cubic foot, power plant efficiency, and CO2 emissions per Btu of natural gas are from DOE EIA publications and conversations with EIA staff in the Electricity Generation and Capacity division of the National Energy Modeling System (NEMS).
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The following units conversion were used to express CO2 emissions in terms of Btu from natural gas required to supply the energy for the maglev system:
5.1.3.3. Increased Emissions Estimate Estimates of increases in CO2 emissions from added natural gas powered electric generation were developed in three steps: • Estimate the energy requirements per passenger per kilometer • Calculate total daily energy requirements for the maglev system based on total passengers and average travel distance • Determine the total natural gas required with two different types of facilities (turbines and combined cycle) to produce the daily energy requirements of the maglev system, and develop estimates of associated natural gas CO2 emissions.
5.1.3.4. Added Energy/Passenger/Kilometer The estimated required energy per passenger per kilometer is calculated as
E pk = [(750/100)3600](244/138)/244) = 195.7 ~ 200KJ/passenger/kilometer
5.1.3.5. Daily Energy Requirements for Maglev Train System Daily energy requirements for the maglev system are estimated as:
5.1.3.6. Natural Gas Requirements and CO2 Emissions Daily natural gas requirements for electric power to support the maglev system are:
NG = daily natural gas requirements
For turbine based power facilities:
For combined cycle based power facilities:
A range of increases in CO2 emissions is obtained for the two different types of power production facilities:
Turbine: CO 21 = (1,460 10° Btu/year)(3.19 x 10lbs/Btu) = 46,570,000 lbs/year.
CO2+ = 21,000 metric tons/year
Combined Cycle: CO2c = (912 x 10° Btu/year)(3.19 x 10lbs/Btu) = 29,090,000 lbs/year.
CO2c = 13,000 metric tons/year
While these first order estimates suggest that CO2 emissions would be larger if natural gas turbines were used to provide power for the maglev system, such findings are preliminary. For example, no estimates of transmission line losses are considered for the combined cycle facility, which would likely be an addition to the current transmission grid. In addition, neither power option considers the possibility of power regeneration during train braking, which would reduce emissions for both types of facilities.
5.1.4. Estimates of Net CO2 Changes Estimated net greenhouse gas emission changes depend on the values assigned to the parameters when estimating emission decreases due to reduced vehicle traffic on 1-70, and when estimating increased greenhouse emissions because of added electric power for the maglev system that would be produced using natural gas. Using the baseline estimate of emission reductions compared with the two types of power facilities considered yields the following results:
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Baseline CO2 reductions vs. combined cycle facility emissions: 27,000 metric tons – 13,000 metric tons = 14,000 metric tons annual CO2 reduction Varying parameters for the estimates of reductions and increases of CO2 emissions would change these values somewhat. However, the net CO2 reductions from use of the maglev system are not large when compared to the estimates of approximately 14 million metric tons of annual CO2 emissions from all transportation-related fossil fuel use in 2000.
5.1.5. Summary The objective of this analysis is to describe the regional environmental effects of developing a maglev transit system along the 1-70 corridor west of Denver, Colorado, defined as CO2 or greenhouse gas emissions. The net greenhouse gas effects are measured in the combination of reductions due to decreased vehicle traffic on 1-70, and increases in emissions from additional electric power sources for the maglev system. This analysis documents the initial baseline estimate of reduced greenhouse gas emissions due to less driving by individuals who divert from the highway system to the maglev system, and the increased emissions from additional power sources for the maglev system. Natural gas is assumed to be the fuel of choice for additional electric power facilities. These are first-order estimates, based on average values for the parameters used in the estimation approaches.
Three parameters used in calculating emission reductions - number of passenger trips, percent of passenger trips diverted to the maglev system, and percent reduction in annual miles driven for train riders - were varied to look at the relative impacts on the baseline emission estimate. The results suggest that the percent of trips diverted to the maglev system and the proportion of reduced miles driven for train riders affect emission estimates more than total passenger trips on the system.
Two types of power generating facilities - natural gas fired turbines and combined cycle turbines - were considered when estimating increases in CO2 emissions to supply added power for the maglev system. The preliminary estimates suggest that use of larger power facilities may result in less CO2 emissions when meeting the additional power requirements. However, other important factors, such a transmission line losses, have not been evaluated.
Net CO2 reductions as individuals divert from passenger vehicles on 1-70 to the maglev system are modest, ranging from 6,000 metric tons to 14,000 metric tons annually when comparing the baseline CO2 reductions case with the CO2 increases for the two different power facilities.
5.1.5.1. References
Colorado Department of Public Health and Environment 2000. 2000 Colorado Gas Emissions
Piyushimita, Thakuria, Deepak Virmani, Seongsoon Yun, and Paul Metaxatos 2002. Estimation of the Demand for Inter-city Travel: Issues with Using the American Travel Survey.
Rote, Donald M., Zian Wang, and Anant Vyas 1996. Methodology for Computing Public Benefits of Diverting Passenger Trips from Conventional Modes to HSGT Modes of Travel, Center for Transportation Research, Argonne National Laboratory, May 1996
Rote, Donald M. 1999. Guidelines for Estimating Trip Times, energy Use and Emissions for HSGT Technologies, Center for Transportation Research, Argonne National Laboratory, October 1999.
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Texas Transportation Institute 2001. Annual Mobility Report.
U.S. Department of Energy, Energy Information Administration 2002. Emissions of Greenhouse
U.S. Department of Energy, Energy Information Administration 2003. Assumptions to the Annual
U.S. Department of Transportation, Federal Highway Administration 2002. Highway Statistics 2001.
U.S. Department of Transportation, Federal Highway Administration 2002.
U.S. Department of Transportation, Bureau of Transportation Statistics 2001. Transportation in the United States: A Review.
U.S. Environmental Protection Agency 2001. Green Book: Nonattainment Areas for Criteria
U.S. Environmental Protection Agency 2002. U.S. Emissions Inventory 2002: Inventory of U.S.
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Table 5.1-4 Annual Emissions and Fuel Consumption for an Average Passenger Car 1
Pollutant Amount/mile? Miles/year Calculation Pollution/year 12500 22g*11b/4549*12500 | 606 lbs. Monoxide Nitrogen 12500 1.59*11b/4549*12500 41 lbs. Oxides Carbon 0.8 lb 12500 0.81b*12500 10,000 lbs. Dioxide Gasoline .044 gallon 12500 .044 gal*12500 550 gal. Source: National Vehicle and Fuel Emissions Laboratory, U.S. Environmental Protection Agency Emission factors and pollution/mile may differ slightly from original sources due to rounding. ? Emission factors come from standard EPA emission models, assuming an average properly maintained car in 1999, operating on typical gasoline on a summer day (72-96°F). Average annual mileage source: EPA Office of Mobile Sources Assessment and Modeling Division. Fuel consumption is based on average in-use passenger car fuel economy of 22.5 miles per gallon.
Table 5.1-5 Annual Emissions and Fuel Consumption for an Average Light Truck (Light trucks include pickups, vans minivans, and SUVs)
Pollutant Amount/mile? Miles/year Calculation Pollution/year Hydrocarbons 3.7 grams (9) 14000 3.79*11b/4549*14000 | 114 lbs. Carbon 14000 29g*11b/454g*14000 894 lbs. Monoxide Nitrogen 14000 1.99*11b/454g*14000 59 lbs. Oxides Carbon 1.2 lb 14000 1.21b*14000 16,800 lbs. Dioxide Gasoline .056 gallon 14000 .056gal* 14000 915 gal. Source: National Vehicle and Fuel Emissions Laboratory, U.S. Environmental Protection Agency Emission factors and pollution/mile may differ slightly from original sources due to rounding. Emission factors come from standard EPA emission models, assuming an average properly maintained Source: US DOT/FHA, Highway Statistics 1999.
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6.0 PROPULSION (TRADE STUDY)
6.1.1. Goals and Objectives A Propulsion Trade Study was conducted to identify and evaluate prospective linear motor designs that could potentially meet the system performance requirements of the CMP and be applicable to other urban maglev transit corridors. The analysis involves the performance of the linear induction motor (LIM) propulsion system of the Chubu HSST (CHSST) that has been selected as the project baseline technology. Potential near-term improvements to the propulsion system and the relative impact of research and development in critical areas were considered. This report presents the results of field-based simulations of the LIM that meets the requirements of the Colorado route, and the sensitivity of performance to parameters modified from existing CHSST designs. These modifications have been reviewed by CHSST and Toyo Denki Inc., and their implementation appears feasible.
6.1.2. Scope and Tasks Identify and characterize the CHSST baseline motor and vehicle, and near-term improvement potential; Evaluate the HSST-200 series motor; Identify the critical developmental elements of the HSST-200; Evaluate the forces that the propulsion system imposes on the levitation system; Evaluate the prospective motor designs that could potentially meet the system performance requirements of the Colorado Project including parameters identified above and potential deployability; Integrate these analyses into vehicle and sub-system requirements and evaluations for the CMP application; Identify and analyze potential improvements and optimization of performance parameters for propulsion sub-systems; Characterize and compare the advantages/disadvantages of the potential performance of the motor types for maglev system application.
6.1.3. Resources and Technical Work
6.1.3.1. Literature Search of Linear Motor Technology An extensive search of open literature was conducted through the Sandia National Laboratories Library using several electronic databases such as INSPEC, NTIS, SciSearch, and TRIS to locate journal articles and reports related to linear motors for maglev systems from 1980 to 2002. Roughly 800 citations were located which typically have an abstract in English. Most of the papers from international conferences are available in English, but many of the cited reports are in German or Japanese as one would expect. The citations have been cataloged in a searchable database using ProCite software. This search has been very helpful in locating references that are published outside of conference proceedings.
Papers on linear motor technology have also been located through the major maglev conferences such as the International Conferences on Magnetically Levitated Systems and Linear Drives (MAGLEV93, 95, 98, 2000, 2002) and the Linear Drives for Industry Applications (LDIA 95, 98, 2001). These proceedings are very useful as the papers are well referenced and reviewed.
ProCite reference manager, version 5, ISI ResearchSoft, Berkeley, Calif. www.procite.com
Several texts on linear induction or synchronous motors have also been located including recent and/or relevant works by lon Boldea and Syed Nasar, 29,6,7,8), Jacek Gieras 19,19), and Eric Laithwaite (11,12,13). Each of these covers a section on high or medium speed transportation applications. The analysis and modeling methods for linear motors discussed in these works have been reviewed.
6.1.3.2. Non-Disclosure Agreements A non-disclosure agreement was executed between Sandia National Laboratories and the Chubu HSST Development Corporation and the Itochu Corporation of Japan that facilitated the exchange of information for the technical evaluation of the HSST propulsion system. Their cooperation, with support from Toyo Denki, provided data, tools, and technical reviews that would not have been available otherwise to execute this study.
6.1.3.3. Technical Consultant A consulting contract was established with Prof. Eisuke Masada of the Science University of Tokyo. He is a world expert in linear motor propulsion and maglev systems, and his expertise provided invaluable support to the assessments and evaluation of the existing propulsion technology and recommendations for improvement.
6.2. THRUST AND POWER REQUIREMENTS
6.2.1. Requirements and Assumptions for Analysis The requirements for the LIM propulsion system are based on the design of the Colorado 200 vehicle, anticipated environmental conditions, and FTA requirements. [14, 15, 16). The requirements are shown in Table 6-1.
lon Boldea and Syed Nasar, The Induction Machine Handbook, CRC Press, Boca Raton, Florida, 2002. lon Boldea and Syed Nasar, Electric Drives, CRC Press, Boca Raton, Florida, 1999. lon Boldea and Syed Nasar, Linear Motion Electromagnetic Devices, Francis and Taylor, New York, 2001. Ion Boldea and Syed Nasar, Linear Motion Electromagnetic Systems, John Wiley and Sons, New York, 1985. Jacek Gieras, Linear Induction Drives, Clarendon Press, Oxford, 1994. Jacek Gieras and Z.J. Piech, eds., Linear Synchronous Motors: Transportation and Automation Systems, CRC Press, Boca Raton, Florida, 1999. E. R. Laithwaite, Induction Machines for Special Purposes, George Newnes Limited, London, 1966. 12 E. R. Laithwaite, Propulsion Without Wheels, Hart Publishing Co., New York, 1968. E. R. Laithwaite, A History of Linear Electric Motors, Macmillan., London, 1987. FTA Urban Maglev Program, CDOT Team report "Task 3, Transit System Performance Requirements," Final Report 1.1, 17 oct02. FTA Urban Maglev Program, CDOT Team report "Task 10, Vehicle Design, Technical Memo 4.1,Vehicle Interior Configuration" 6Jun03. FTA Urban Maglev Program, CDOT Team Quarterly Review Meeting, Washington, D.C., 9Jul03.
Table 6-1: Parameters and system requirements for analysis of required thrust and power
Vehicle mass, loaded: 44 tonne COL-200a, Vehicle length, width, and height: 24.3 m, 3.2 m, 3.5 m COL-200a Vehicle Drag: Drag force for COL-200a modified to allow for possible reduced drag.
An assessment of the thrust and mechanical output power required for the linear motor was done to establish how closely the existing HSST linear induction motor (LIM) met requirements, and the desired motor's thrust performance curve. This analysis is a point-mass model that considers the drag, grade climbing, and acceleration for a train of several vehicles. The drag force has contributions from aerodynamic loading with headwind, magnetic drag, and power collector friction. The required force is divided by the number of cars in the train to obtain a total force per car as the unit of measure.
Examples of the total drag force and components of that force on the Colorado 200 vehicle without the effect of additional headwind are shown in Figure 60. The influence of a strong head or tail wind is shown in Figure 61. However, these forces are small compared to the required force per car to propel the vehicle up various grades as shown by the drag force (now including grade climbing force) in Figure 62. The required thrust force per car shown in Figure 62 is based on the combined requirement of accelerating the Colorado 200 vehicle from rest at 0.16 g and maintaining the maximum speed of 160 kph on a 7% grade.
The required thrust per LIM is derived by dividing the total thrust required per car by the planned 10 levitation/propulsion modules for the Colorado 200 vehicle. The LIM proposed for this module has been extended 27% longer than the existing HSST-200 LIM design to increase thrust. The thrust requirement and capability of the scaled, existing design are shown in Figure 63. Two maximum thrust levels are shown, one for 0.16 g acceleration (required level), and the other at 0.11 g for reference.
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Figure 60: Total drag force for 2-car consist of HSST-100L or Colorado 200 vehicles, and the components of the drag without additional headwind on level grade.
Figure 61: Influence of head or tailwind on the total drag for 2-car consist of Colorado 200 vehicles on level grade.
Colorado Maglev Project Part 3: Comprehensive
Figure 62: Drag Force (including grade climbing force) per Colorado 200 vehicle based on 2-car consist with a 90 kph headwind.
Red thrust curve is based on achieving 0.16 g acceleration on level grade from rest, and maintaining speed of 160 kph climbing 7% grade.
Figure 63: Required thrust per LIM for Colorado 200 vehicle and capability of scaled HSST-200 design based on 2-car consist into a 90 kph headwind.
6.2.2. Electric Power per Car Along Route For the Electrification effort, an estimate was made of the thrust and electric power required per car to propel a 2-car consist of Colorado 200 vehicles at constant speed of 114 kph on 1-70 from DIA to Eagle County Airport. The route data is the westbound data set from a GPS survey of l70. ('?] This is not suggested to be the actual proposed route for the 1-70 corridor, but was the best data available at the time of the analysis.
The original latitude-longitude-elevation GPS data was slightly modified for the analysis. The first 143 points were deleted as their path is highly irregular. This removes only about 2 km at DIA from the 240 km route. The data was then sampled at 5-point intervals to reduce the number of points from over 11,000 points to 2200 to speed the calculations. The average distance between samples increases from 21 m in the raw data to 109 m, although the coarser sampling is sufficient to represent the route grade and curvature. The latitude-longitude-elevation data was then converted to X(east-west distance), Y(north-south distance), and Z(elevation change) in meters relative to the first point near DIA which is defined as the origin (x,y,z = 0,0,0). The location of this origin is (39.834 deg N latitude, -104.682 deg latitude, 1627 m elevation). To eliminate single-point noise, the sampled original data was filtered with a 5-point moving average taken with a Gaussian weighting distribution over the five points.
For this estimate of power demand an assumption of constant velocity is used. This analysis determined the thrust that is necessary to overcome contactor friction, magnetic and aerodynamic drag, and grade. The speed of 114 kph is the average speed obtained over the route from analysis that includes limitations due to lateral accelerations from route curvature. [18] A 90 kph headwind was also included to obtain an upper bound estimate of power, as this is the maximum operable wind condition for the HSST-100 system.[19] From the required thrust, the mechanical power is derived, and the electrical power is determined from estimated LIM motor and other efficiencies.
Figure 64 shows the westbound grade and elevation change plotted along with the Y coordinate. Note that several of the variables have been scaled to fit the graph, such as Z, or elevation change, has been divided by 20 in the plot. This was done so the abscissa-ordinate scaling was kept at 1:1 and the Y coordinate on the chart could be read also as a map. Locations of several possible power pickup points are also shown along the route path. The shape of the elevation curve appears slightly distorted because all points are plotted with respect to the x-coordinate, not distance along the route.
Figure 65 shows the electric power required per car traveling westbound or eastbound with a 90 kph headwind. Of course, this condition would not occur simultaneously, but the values represent high-power conditions for each direction. Note that the abscissa for this plot is the distance along the route, not the east-west distance. The electric power required per car is based on the required thrust curve (0.16 g) in Figure 66, the estimated efficiency of the LIM, and a 90% forward rectification and transmission efficiency of the DC power to the vehicle. The negative power value represents power from regenerative braking, but a very low, conservative efficiency of 35% is assumed for the power returned to the utility in this example based on lower efficiency of bi-directional inverter/rectifiers and previous user's experience. 1297 Present plans are not to return the power to the utility, but use regenerated power for on-board loads or within the stationvehicle power system.
David Munoz, "1-70 GPS Survey," Technical memorandum, October 14, 2002. FTA Urban Maglev Program, CDOT Team report "Task 14, Integration, Technical Memo 4.0," 22Apr03. FTA Urban Maglev Program, FTA Assessment Team report "Assessment of CHSST Maglev for U.S. Urban Transportation," July 2002, pp. 6-11. Private communication, Prof. E. Masada, Science Univ. of Tokyo, 2003.
Figure 64: Map of 1-70 where the origin of coordinates is DIA
Horizontal is east-west distance, and vertical is north-south distance, elevation change divided by 20, or grade times 1000. Power locations are located by circles along route.
Figure 65: Electric utility power required per COL-200 vehicle for 2-car consist westbound or eastbound at 114 kph along route, with 90 kph headwind.
6.3. OPTIONS FOR IMPROVEMENT OF CHSST LIM TO MEET REQUIREMENTS A series of independent meetings was held in early June 2003 in Japan with linear motor consultants and commercial suppliers of maglev and LIM-driven urban transit systems to assess the capability of existing systems, and the feasibility of eleven proposed changes for the HSST LIM drive. These proposed changes resulted from several weeks of prior consultation with Prof. Eisuke Masada of the Science University of Tokyo, and Dr. Takafumi Koseki of the University of Tokyo, who has studied under and worked with Prof. Masada. A two-day meeting was held with staff from Chubu HSST Development Corp., Toyo Denki Seizo, and ITOCHU Corp. to negotiate the proposed motor improvements. In addition, a separate meeting was held with staff from Hitachi's Research Lab and Mito Transportation Systems Division to discuss their linear induction motor and wheel-based urban transit technology currently employed in Japanese subway systems.
These options to improve the linear motor performance range from low difficulty (options 1 through 7) to significant difficulty (options 8 through 11) to incorporate:
Increasing the maximum voltage per LIM to permit the motor to operate at constant Voltage/frequency mode to a higher "breakpoint" speed (rated speed), and to permit operation at constant mechanical power at speeds greater than the breakpoint speed.
Colorado Maglev Project Part 3: Comprehensive Page 14
2. Increase the trolley rail differential voltage to 3000 VDC to permit higher motor voltage, reduce trolley rail current, and potentially reduce the size of the on-board inverter and power conditioning equipment. 3. Change the operating point on the motor's thrust vs. slip frequency characteristic curve toward lower slip frequencies to achieve greater thrust and higher efficiency. 4. Increasing the primary current of the LIM to sufficient values to achieve the required thrust for the 0.16 g acceleration (7 kN/LIM) for a very short duration. 5. Use forced air (or liquid) cooling to prevent overheating of the primary winding to achieve higher thrust at speeds greater than the breakpoint, when higher operating power level is steady-state. 6. Decrease the length of the clearance gap between the LIM and the reaction rail. 7. Utilize solid copper reaction rail in regions of track where higher thrust is needed such as on high-gradient and in station. 8. Utilize two inverters on-board the vehicle and configure the primary windings such that the number of stator poles is small for low-speed operation, but then the phase of the inverters is changed to double the number of stator poles for high-speed operation. 9. Utilize concept of double-fed LIM in regions of track where higher thrust is needed such as on high-gradient and in station. In this case the reaction rail sheet is replaced with a winding on a core similar to the stator, but energized by a separate power supply. 10. Utilize long-stator LIM in guideway where higher thrust is needed IN ADDITION to the existing on-board, short-stator LIM. 11. Incorporate permanent magnets or separately energized coils near the entry end of the LIM to compensate for deleterious end-effects at high speed.
The consensus of the team was that a combination of Options 1-7 for the existing LIM design of the HSST-200 was considered sufficient to yield a LIM design capable of driving a COL-200 vehicle on the Colorado route and meet the requirements of 0.16 g acceleration from station and 160 kph speed on 7% grade. It was recognized that concomitant with the increased thrust, there is increased normal force that has an impact on the levitation system. Each of the options 1 through 7 has been modeled to assess the magnitude of the impact to other systems and the requirements for the inverter.
6.4. CODE DEVELOPMENT TO MODEL LIM PERFORMANCE A LIM performance model was generated based on Prof. Yamamura's method 24) and techniques further developed by Dr. Takafumi Koseki from the thesis by Dr. Keisuke Fujisaki, both of the Univ. of Tokyo. (22) 'This model previously demonstrated very good agreement with performance of the HSST-03. Calculations using parameters for a HSST-200 design were done using 1989 parameters, and the results of that early analysis were replicated.
Further calculations were made to compare with HSST-200 calculations that have been completed by CHSST and Toyo Denki with their own codes based on Prof. S. Nonaka's method
Sakae Yamamura, Theory of Linear Induction Motors, Second edition, Univ. of Tokyo Press, Tokyo, Japan, 1978. Keisuke Fujisaki, "A Study on Electromagnetic Suspension Controlled Magnetically Levitated Train," doctoral dissertation, Univ. of Tokyo, December 21, 1985. Page 15
Force (N), LIM Phase Voltage (V), 1 dc/vehicle (A)
Frequency (Hz) Slip (%) PF (%) Efficiency (%) Phase Voltage (V) Current (A) Thrust (N) Attraction (N) DC Currentvehicle (A)
with updated spatial harmonics analysis code using parameters labeled HSST-200 14Jan03c in Table 6-2. DC current/vehicle is for all inverters on vehicle feeding 6 LIMs.
Other features to note in Figure 68 are that the current and voltage shown are per LIM and from the input parameters in Table 6-2; the 6 LIMs considered per vehicle are in a 2-series (delta) configuration with 3 groups in parallel. The curve labeled DC current/vehicle is the current to power these 6 LIMs. The voltage on the trolley power rails +1500 VDC to ground for this calculation. This configuration results in the inverter output line-to-line voltage reaching its limit (including derating factors) at about 130 kph. The efficiency shown is the LIM efficiency at the inverter, and the 91% efficiency of the power conditioning equipment must be considered to obtain the efficiency at the trolley rail.
6.5.2. Modifications to HSST-200 Baseline LIM While the thrust of the HSST-200 LIM is significant, even if the length of the motor is increased 26% to fit the length of the bogie in the COL-200 vehicle and the thrust increased proportionally, Figure 68 shows that additional changes are needed to achieve 7 kN at low-speed and 4 KN thrust/LIM at 160 kph. The options 1-7 for modification discussed above were considered in a sequence where calculations were made for a range of values for the changed parameter. Over forty calculations were conducted with parameters that are discussed below as part of the optimization to achieve the desired thrust values. One resulting configuration of parameters is shown in column labeled 'COL-200 110ct03b' in Table 6-2. The cells that are highlighted yellow signify that the parameter value has changed from the HSST-200 case.
Colorado Maglev Project Part 3: Comprehensive 1. LIM length is increased to 2.91 m to generate greater thrust per LIM. This increase in
length is done by keeping the slots width (direction of motion) and pitch the same as the HSST-200. However, the number of poles was increased from 8 to 10. The 2.91 m length is within the length of the COL-200 vehicle bogie.
2. To keep a high thrust-breakpoint speed, the number of turns per phase was decreased by decreasing the number of turns per preformed primary winding coil from 5 to 4. The wire thickness was then increased 20% to make use of the available space in the slot.
3. There are 10 LIMs per vehicle, and 2 cars per married-pair consist. For the calculation "COL-200 11octo3b', the 20 LIMs are configured in a 4 series-5 parallel, 3-phase delta configuration that is considered powered by a single inverter for the purposes of the code. It is more likely that multiple, parallel inverters will energize the LIMs of each vehicle. For calculation 'COL-200 19 nov03a', the 10 LIMs per vehicle are configured into two groups of 1 series-5 parallel, 3-phase WYE configuration, where each group is energized by its own inverter. This WYE configuration simplifies cabling between LIMS and balances the number of LIMs per inverter. The current into each LIM for either of these configurations is the same.
4. LIM maximum current increased from 280 A to 386 A to generate 7000 N low-speed thrust. Thrust scales as the square of the LIM current if the iron of the primary core can support the increased flux.
5. The difference in voltage between the trolley rails is increased from 1.5 kV to 3 kV DC. The increased voltage provides options to put more LIMs in series and increase the maximum voltage output of the inverters. CHSST staff has noted that 3 kVDC systems are not used in Japan, and there may be a limited number of Japanese manufacturers. (29] However, Hitachi is manufacturing 3 kV rail power conditioning equipment for Russian rail systems and there is an additional manufacturing base in Europe of this equipment that is used in Spain, Italy, and Poland. Three kilovolt systems have been used for rail systems traveling up to 250 kph in Italy from Rome to Florence. (28) The 4 series – 5 parallel, 3-phase delta configuration of calculation 'COL-200 110ct03b' uses trolley voltages at +3 kV DC and ground. In calculation 'COL-200 19nov03a', one set of 1 series - 5 parallel LIMs is energized by an inverter fed from +1.5 kV and ground trolley rails, and the second set of 1 series - 5 parallel LIMs is energized by an inverter fed from the ground and -1.5 kV trolley rails. This latter configuration makes use of the more prevalent 1.5 kV inverters used in conventional rail systems.
6. Clearance gap decreased to increase thrust, but the attractive normal force also increases as shown in Figure 69. Gap value of 13 mm selected based on recommendation by CHSST and Toyo Denki staff for minor change. Note that calculations include additional 1 mm of air gap added to the clearance gap for the adhesive between secondary rail conductor and back iron.
7. Changing the reaction rail from aluminum to copper and varying its thickness and/or the slip frequency has a significant impact on the low-speed thrust and attractive force, but does not yield much improvement in thrust at 160 kph compared to the 4 mm aluminum. This is seen in Figure 70. Replacing the aluminum rail with a copper rail whose 3.2 mm thickness is the same fraction of the classical electrical skin depth reduces the thrust and attractive force. Decreasing either the slip frequency or the thickness to increase the thrust also dramatically increases the attraction force. Given that LIM efficiency changes only by 2 to 3 percent at both the breakpoint speed and at 160 kph compared to the 4
Trainspotting Bukkes, www.bueker.net/trainspotting/voltage comparison, 2003.
Colorado Maglev Project Part 3: Comprehensive mm thick aluminum, changing to a copper rail does not appear warranted due to the cost, unless the clearance gap is further decreased significantly and additional shielding of the attractive normal force is needed.
8. For the calculation 'COL-200 11octo3b' with 4series-5 parallel LIMs, the maximum inverter line-to-line voltage (peak) increased from 1100 V to 2450 V consistent with the increase of the trolley voltage from 1.5 to 3 kV DC to achieve a high thrust-breakpoint speed. With 4 series LIMs, this sets the maximum voltage per LIM at 550 Vrms. As seen in Figure 71, this change has the most direct effect on increasing the thrust at 160 kph to the required 4000 N.
For the calculation 'COL-200 19nov03a' with 1series-5 parallel LIMs, no increase in lineto-line voltage is needed with the LIMs in a WYE configuration, the maximum voltage per LIM reaches 570 V, achieving the same thrust profile.
9. Wire height was increased 10% from 14 to 15.4 mm to achieve the same Ohmic power dissipation per unit volume as obtained in the HSST-200 14jan03c calculation, 1.05 W/cm3. Height of the primary core slot is increased to accommodate this increase. This does not affect the calculated output given that the primary core cross-section is maintained.
50 100 150 200 Speed (kph) Figure 69: Sensitivity of LIM thrust and attractive normal force to change in clearance gap between LIM and reaction rail.
Figure 70: Sensitivity of LIM thrust and attractive force to reaction rail conductor type and thickness.
50 100 150 200 Speed (kph) Figure 71: Sensitivity of LIM thrust and attractive normal force to the maximum voltage per LIM adjusted by varying the maximum inverter output line-to-line voltage.
10. The total Ohmic power dissipated per unit length of LIM is only 9% greater than the value estimated from the HSST-200 calculation (7.6 kW/m). It is expected that no additional cooling system is needed to augment the flow of ambient air used in previous CHSST designs. [29] However, design of vehicle chassis with ducting to preferentially force air across the LIM winding ends when moving may be beneficial to remove the additional heat.
11. The calculations shown above utilized a relative permeability of 500 for the secondary back iron, the value that was the default in the code. It is believed that this value is too high for bulk carbon steel and that a value of 100 is more conservative. The sensitivity of the thrust and attraction curves for relative permeabilities of 50, 100, 200 and 500 are shown in Figure 72. The impact of the relative permeability is significant for the lowspeed thrust, but much less so at 160 kph. The impact on the attractive force is more dramatic.
12. Neither a permeability vs. magnetization curve nor a B-H curve was available at the time of this analysis for the back iron of the secondary rail used by CHSST. Currently, a search is underway for data of the magnetic properties for the (Japanese Industry Standard) SMA 400AW low-carbon, atmospheric corrosion-resistant steel or its U.S. equivalent. Data on permeability for low-carbon steels that are common to reaction rails is shown in Figure 73. Ở The estimate of a relative permeability of 100 is a conservative value based on the common carbon steel data for the anticipated 6700 A/m field intensity
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5 10 15 20 Slip frequency (Hz) Figure 76: LIM thrust and attraction force vs slip frequency parameterized by speed for parameters in COL-200 11octo3b in Table 6-2
Vector in thrust curve show recommended change in slip frequency after the breakpoint speed of 120 kph to increase thrust at 160 kph. Page 17
Table 6-3: Summary of output values from calculations for HSST-200 and COL 200 LIMs using input parameters in Table 6-2.
The maximum attraction force has increased from 3163 N per LIM for the 33 tonne, 6-LIM HSST200 vehicle to 4169 N per LIM for the 44 tonne, 10-LIM COL-200 vehicle. Most of this increase is associated with the 26% increase in length of the LIM as expected, and the vehicle will have additional levitation magnets to support the longer, heavier vehicle. The attractive force from the six LIMs of the HSST-200 is 19 KN which represents about 6% of the loaded vehicle mass. The attractive force from the ten LIMs of the COL-200 is 42 - 45 kN which represents about 10% of the loaded vehicle mass. CHSST staff has indicated that while the change is not negligible and attention must be given to the limits of the levitation control system, the problem is not critical. In addition, future advances in levitation control and magnet design will also support mitigation of the impact of the normal force. (29)
The inverters that feed the LIMs have been sized to deliver up to 10% greater current than the 386 A normal operating level. This is done to provide a margin in capability in normal operation and permit emergency braking at high acceleration. Figure 77 shows the thrust curves for the normal and maximum LIM current levels and the drag force/LIM for the 44 tonne vehicle in a 2car married pair configuration with a 90 kph headwind. A 15% climbing grade appears to be a practical limit under normal operating conditions, while 18% may be possible at maximum current for short durations. If steady operation at the maximum current is considered, additional forcedair (or possibly liquid) cooling of the LIM will be needed.
Review of Propulsion Trade Study LIM modifications and calculations, CHSST and Toyo Denki, 21oct2003.
Figure 77: Thrust per LIM at normal operating current of 386 A and maximum inverter output. Drag force/LIM curves for married pair of COL-200 vehicles on various grades into a 90 kph headwind at zero acceleration. a
6.5.4. COL-200 LIM Braking Performance In the braking mode, the slip frequency is changed from +11.5 Hz to -11.5 Hz that sets the traveling magnetic wave of the LIM slower than vehicle speed by the amount of the slip frequency times twice the pole pitch. This puts the LIM into a regeneration mode where energy from the vehicle is converted to electrical power that can be delivered back to the trolley line. This is seen as a negative current delivered to the vehicle in Figure 78 that also shows curves for the frequency, LIM voltage and current, power factor and efficiency. The regeneration mode is used from 160 kph down to 22 kph at which point the frequency crosses zero. At lower speeds, the sequencing of the three current phases to the LIM is changed to cause the traveling magnetic wave to reverse direction and travel opposite the vehicle direction, putting the LIM into plugging mode which still delivers braking force, but now the vehicle absorbs power from the trolley line. The braking and normal forces are shown in Figure 79.
The braking force curve shows significant braking capacity up to the maximum operating speed of 160 kph. Considering a 44 tonne vehicle with a 90 kph tailwind, an estimate was made of the stopping distance and time on descending grades under constant magnetic braking force of 67 kN (normal duty) or 80.3 kN (emergency duty) per car. No friction braking is considered in this estimate. The higher force assumes a 10% increase in the LIM current for emergency braking conditions or on high descending grade. The results for an initial speed of 160 kph are shown in Figure 80. A descending grade of -15% is the practical limit for normal current level operation, using the maximum inverter current. At -18% grade, the braking force is only sufficient so speed does not increase, and significant deceleration would take place when the vehicle reached shallower grade.
Figure 78: Electrical performance curves for COL-200 LIM in braking mode with 386 A/LIM and slip frequency of -11.5 Hz.
Figure 79: Braking and normal force for COL-200 LIM with 386 A/LIM and slip frequency of -11.5 Hz. Other LIM parameters are same as case 19 nov03a in Table 6-2.
Figure 80: Braking deceleration and distance for 44 tonne COL-200 vehicle with initial speed of 160 kph as a function of grade.
6.5.5. Development Plan for Improved Motor Design During meetings held in early June 2003 in Japan with staff from Chubu HSST Development Corp., Toyo Denki Seizo, and ITOCHU Corp., technical options were discussed to improve the HSST-200 LIM to meet the requirement of the Colorado route. As described in Section 6.3 above, Options 1-7 were considered viable, and these formed the basis of the tradeoffs analysis above.
At that meeting, discussions were held concerning the resources and time required to incorporate the suggested options in a LIM design, and the effort required to produce the first motor for fullscale testing. Although the modifications to improve LIM performance recommended in this study are only a subset of those contemplated at that time, the estimate is believed valid.
This is only a rough estimate based on CHSST and Toyo Denki recent experience with the TKL. This estimate would be modified early in the Basic Design phase and depends upon which options for LIM modification are selected and their impact. The development plan shown in Figure 81 has three design phases: 1) Basic Design performed by CHSST and Toyo Denki focuses first on motor details, then issues related to the motor and its configuration and impact to the vehicle; 2) Detailed Design again involves staff from CHSST and Toyo Denki and addressed details and issues of motor and vehicle; 3) Design for Manufacturing is conducted by Toyo Denki alone and generates the manufacturing process and final drawings of the motor and necessary tooling. In Japan, this production specification and drawings remain the property of the manufacturer, not the customer. This design work is part of the procurement of the motor, and does not start until a contract for fabrication is placed.
Colorado Maglev Project Part 3: Comprehensive
Figure 81: Rough schedule for development of LIM with improvement options and generate first article for testing.
This estimate may be modified early in the Basic Design depending upon which modification options are selected.
6.6. INVERTER AND PROTECTION CIRCUITS As discussed above, two configurations of LIMs were considered as loads to the inverter: a 4 series-5 parallel 3-phase delta configuration of the 20 LIMs for the two-car consist, and four groups of 1 series-5 parallel wye (star) configurations where each group would be energized by its own inverter. The goal for each case was to utilize a 3 kV differential between the trolley lines and for the inverters to have sufficient input voltage to achieve 550 Vrms output to drive the necessary current through the LIM to achieve the desired thrust. A trolley line voltage difference of 3 kV is desirable to minimize the current that must transfer through the power collector on the vehicles. A 1.5 kV voltage differential would require 4520 A at maximum power per 20 LIMs of a two-car consist compared to 2260 A draw at 3 kV differential. The lower current could be supported by a single trolley rail about twice the overall cross-section dimensions of the existing rail (but solid instead of tube) used at the Nagoya Test Track and result in voltage drop of only 30 V/km or 1% per kilometer.
Collection of the high current from the trolley line must be demonstrated at the maximum speed of 160 kph. The collector for the HSST-Linimo maglev vehicle to be used on the Tobu-Kyuryo Line (TKL) in Nagoya, Japan is shown in Figure 82. It has a maximum current capacity of 600 A with a trolley rail contact height of 13 mm, and has operated up to 110 kph with collector wear on the order of 0.6 mm/1000 km (9). Extending the capacity to 1130 Alvehicle will require a rail that is 23 times wider to handle the current and reduce the wear. Testing of a modified collector designs could be conducted at the Railway Technical Research Institute Test Track at Kokubunji, Tokyo to determine the collector stability and wear characteristics.
"Report of Economic Feasibility Study of Levitation Linear Motor Car for Urban Transportation," Japan Transportation Economics Research Center, Aichi Prefecture, March, 1993.
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additional mass/space of cooling and snubber circuits. [] Collaboration with power-conditioning equipment manufacturers will be necessary to insure low-weight and small-volume objectives are met consistent with the required performance.
6.8. SUMMARY AND CONCLUSIONS A propulsion trade study has been conducted to identify and evaluate prospective linear motor designs that could meet the system performance requirements of the CMP, and potentially be applicable to other urban maglev transit corridors. This study has focused on the technical characteristics and performance of the linear induction motors used in the Chubu HSST maglev system that had been selected as the project baseline technology.
This work was done in close collaboration with Prof. Eisuke Masada of the Science University of Tokyo, a world expert in linear motors, the power electronics systems that drive them, and maglev systems, and senior staff from Chubu HSST Development Corp. and Toyo Denki Seizo. Their efforts and cooperation have made this analysis possible.
1) The thrust requirements of the 10 LIMs in the 44-tonne, COL-200 vehicle have been defined based upon the requirements for 0.16 g initial acceleration and ability to maintain speed climbing a 7% grade at 160 kph with a 90 kph headwind. The low-speed thrust per LIM is 7000 N and 4000 N at 160 kph. 2) Peak power demand along the route is estimated between 2 - 2.5 MW/vehicle based on an analysis at constant speed of 114 kph. Details have been used in the electrification analysis. 3) HSST-200 LIM has been designed for 200 kph operation on shallow grade, and modifications to the design are necessary to increase the thrust at low-speed and at maximum speed to meet requirements for the COL-200 vehicle. Eleven options were considered and reviewed with CHSST and Toyo Denki staff in Japan with seven modifications considered for further evaluation. The selected options included: a) Increasing the maximum voltage per LIM to permit the motor to operate at constant voltage/frequency mode to a higher "breakpoint". b) Increase the trolley rail voltage differential to 3000 VDC to permit higher motor. c) Change the operating point on the motor's thrust vs. slip frequency characteristic curve toward lower slip frequencies to achieve greater thrust and higher efficiency. d) Increase the primary current of the LIM to sufficient values to achieve required thrust. e) Use forced air (or liquid) cooling to prevent overheating of the primary. f) Decrease the length of the clearance gap between the LIM and the reaction rail. g) Utilize solid copper reaction rail in regions of track where higher thrust is needed such as on high-gradient and in station. 4) A LIM performance model was generated from previous work developed at University of Tokyo using Prof. Yamamura's method. Although the code was well benchmarked for the HSST-03 LIM, the impedance model needed additional work to permit analysis of a broad range of LIM parameters. This work demonstrated the importance of using the measured LIM parameters to establish the model and the sensitivity of the improvement options under consideration. 5) The LIM code developed by CHSST based on Prof. Nonaka's spatial harmonic method was reviewed in detail, modified to improve the data input and calculation output, and configured
Private communication, J. Kato, Chubu HSST Development Corp., M. Murai, Toyo Denki Seizo, K.K. and Prof. E. Masada, Science Univ. of Tokyo, 2003. Page 19
FTA Urban Maglev Program, CDOT Team Quarterly Review Meeting, Washington, D.C., 9 Jul03. David Munoz, "1-70 GPS Survey," Technical memorandum, October 14, 2002. FTA Urban Maglev Program, CDOT Team report "Task 14, Integration, Technical Memo 4.0," 22Apr03. FTA Urban Maglev Program, FTA Assessment Team report "Assessment of CHSST Maglev for U.S. Urban Transportation," July 2002, pp. 6-11. Private communication, Prof. E. Masada, Science Univ. of Tokyo, 2003. Sakae Yamamura, Theory of Linear Induction Motors, Second edition, Univ. of Tokyo Press, Tokyo, Japan, 1978. Keisuke Fujisaki, “A Study on Electromagnetic Suspension Controlled Magnetically Levitated Train," doctoral dissertation, Univ. of Tokyo, December 21, 1985. S. Nonaka and K. Yoshida, “Analysis of Linear Induction Motors Using a Space Harmonics Technique," Chapter 8 in Transport Without Wheels, E. R. Laithwaite ed., Paul Elek Scientific Books, London, 1977. pp. 187-216. Y.Higasa, "Comparison of the Method of Calculating LIM Characteristics Based On Spatial Harmonic Theory Against Experimental Data," Chubu HSST Technical Report, 12Nov91. Y.Takahashi, “Test Apparatus of Linear Induction Motor for Train," Dengakuronn D, vol. 110, 1990-2. Private communication, Prof. Takafumi Koseki, University of Tokyo, and Prof. Eisuke Masada, Science University of Tokyo, Tokyo, Japan, 5jun03. Data from Chubu HSST Corporation, Nagoya, Japan. Trainspotting Bukkes, www.bueker.net/trainspotting/voltage comparison, 2003. Review of Propulsion Trade Study LIM modifications and calculations, CHSST and Toyo Denki, 21oct2003. "Report of Economic Feasibility Study of Levitation Linear Motor Car for Urban Transportation," Japan Transportation Economics Research Center, Aichi Prefecture, March, 1993. Private communication, J. Kato, Chubu HSST Development Corp., M. Murai, Toyo Denki Seizo, K.K. and Prof. E. Masada, Science Univ. of Tokyo, 2003.
Colorado Maglev Project Part 3: Comprehensive Page 20
Figure 86: Close-up of propulsion/levitation module for LIM.
Primary winding and core on vehicle
Figure 87: Side-view, cross-section of single-sided LIM components.
Figure 88: Block diagram of the power circuit for the LIM.
The power feeder shown in Figure 88 is a solid rail carrying DC power (or AC single-phase) such as is currently used in conventional railways. The power collectors are the vehicle's sliding or wheel contacts to the power feeder. Sliding collectors have been operated up to 130 kph at the CHSST Nagoya test track, though testing facilities for higher speed operation exists at the Railway Technical Research Institute (RTRI) Test Track in Kokubunji, Tokyo. Wheeled collectors have been tested up to 200 kph at the RTRI for the DC linear motor car project.
The on-board power converter conditions input DC or AC power from the power feeder to the appropriate variable-voltage, variable-frequency, multi-phase power needed for LIM operation. The converter also contains input and output filters. This equipment is widely used in conventional high-speed urban railways. The linear induction motor as shown is a single-sided structure that generates a non-uniform normal force, side force, and rotational moments on the LIM. Its operation is less efficient compared to conventional rotary induction motors because of the large air gap between the on-board stator and guideway rail resulting in a high leakage flux. This motor has been used in public transportation by the HSST and Linear Metro Subway in Japan. A double-sided LIM with stator windings and cores on both sides of the guideway reaction rail was developed and tested, but the geometry is very difficult to implement with a small clearance gap.
Finally, the passive reaction rail in the guideway consists of an aluminum or copper plate backed by iron. It is structurally very simple and can be integrated with the levitation rail, as is the case with the HSST. The rail's performance and durability has been tested thoroughly for the development of the HSST maglev system and the steel-wheel Linear Metro subway in cooperation with the Japanese Ministry of Transportation.
7.2.2. Advantages A significant advantage of the LIM drive is that the on-board power conditioning system and construction is very similar to that used in conventional urban and high speed electric railway vehicles. This is important from several perspectives. Many of the power conditioning equipment system sections and components are common, and there exists a significant database of practical experience and design with manufacturers and line operators. The basic technology has been well established, and the technical step to move from rotary induction motor drives for steel-wheel vehicles to LIM propulsion is not large. The incentive for this transition to LIM propulsion is the all-weather capability to negotiate tight curves and steep grades, and meet precise stopping requirements with high deceleration that is not possible with power-driven steelwheels. From the perspective of the public consumer, the transition provides improvement in service and ride quality, and meets their expectations of safety and reliability for transit systems.
The LIM utilizes a very simple reaction rail track, hot-rail power pickup on the vehicle, and passive guideway rails which simplifies the track switches. The reaction rail can be installed discretely along the track, if needed. Vehicles with different design and performance parameters are easily adaptable without changes to the guideway within the guideway load (electrical and mechanical) limits. The guideway can provide small radius horizontal and vertical curves, and a bending switch similar to monorail is applicable. The simple, passive guideway system has been shown to be as safe and reliable as a conventional rail track.
A LIM-driven transit system has a great degree of flexibility to respond to variable or uncertain demand. This includes adjusting the number and size of vehicles on a short-term or long-term basis. In the short term, the ability to add and move vehicles provides rapid response capability for the operator to volatile demand and the recovery from any off-normal shutdown or schedule deviation. In the long-term, if additional power is needed to accommodate an upgrade in the system capacity, the impact to the guideway is almost negligible with the addition of way-side power electrification and conditioning equipment. To meet operational requirements, the block control can be easily adjusted with little, if any, modification to the civil structures.
7.2.3. Disadvantages In general, the energy efficiency of the LIM is lower than the rotary induction motor and the LSM. With the rotary induction motor, the airgap between the stator winding and the rotor is much smaller (a few millimeters) since the gap does not vary, which results in greater efficiency. Air gaps of 10-15 mm are used for LIM drives due to clearance requirements with a varying gap from the vehicle suspension. The on-board LIM primary winding provides all the power that generates the gap field and the induced currents in the reaction rail. As such, with the larger air gap the efficiency is lower than the LSM which uses electro or permanent magnets for the field winding. The weight and size of the on-board power conditioning equipment must also be larger as must the size of the wayside power systems. This increase in weight is what limits the operational speed capability of the LIM-driven system to 200 - 250 kph since the weight penalty makes higher speed operation impractical. However, this is not to say that the efficiency of the LIM is impractical. For the Colorado 1-70 route the anticipated average and maximum speeds are 144 and 160 kph, respectively. For this route, higher speeds did not provide significant advantages, but the maximum speed of -225 kph could be obtained with the COL-200 LIM-driven vehicle. The electrical-to-mechanical efficiency of the LIM at the power pickup hot-rail is 70% at the average speed and 77% at maximum speed.
With the LIM there are also 3-dimensional forces that may influence ride quality. This is due to the coupling between the thrust and the attraction/repulsion force between the primary stator and the reaction rail (commonly referred to as the normal force), and the coupling between these forces and the guiding/decentering lateral force which is transverse to both these forces. Because of eddy currents in the secondary, these forces are not uniform along the LIM in the direction of vehicle motion. These forces do not preclude the utilization of the LIM for propulsion; however, they must be accounted in the design of the guidance and levitation systems. Issues such as harmonics in the normal force and the magnitude of normal and lateral forces at high thrust must be considered as well as the changes in these forces with primary-secondary clearance gap. If the air gap length between the primary and the reaction rail is reduced, the normal force between them becomes larger which can disturb the performance of the levitation system. This being said, it must be noted that LIM-driven systems have been successfully operated at 100 kph and designed for operation at 200 kph mitigating these issues. This coupling of forces also exists for the linear synchronous motor, but forces are uniform along the track due to the laminated structure of the active rail. In designs such as the Transrapid Maglev system, the levitation and thrust forces are applied within the same physical structure and air gap which reduces the mechanical moments applied to the propulsion-levitation bogie module on the vehicle, lessening the requirements of the levitation control system to accommodate the force perturbations.
7.3. LONG-STATOR LINEAR SYNCHRONOUS MOTOR DRIVE
7.3.1. Basic Configuration LSM drives with electromagnets were developed and are utilized for the German Transrapid maglev system for high-speed transportation. This system has been tested in Emsland, Germany since 1984, and is now applied to the 30 km Shanghai Pudong Airport connection to city-center. A very low-speed system for urban applications, the German M-Bahn, was utilized in Berlin for a few years beginning in 1988 as a demonstration track.[38]
The basic system construction of the long-stator linear synchronous motor (LSM) drive is shown in Figure 89 through Figure 91. Figure 89 shows the Transrapid TR08 maglev vehicle that is the type of vehicle being installed in the Shanghai airport-city connector line. As with the LIM-driven
Transrapid International, Transrapid Maglev System, Klaus Heinrich and Rolf Kretzchmar, eds., HestraVerlag, Darmstadt, 1989. Innovative Magnetic Transit System M-Bahn, AEG brochure 1989. See Figure 4, page 52.
system, propulsion-levitation modules that wrap around the guideway are located on each side of each vehicle. Each module contains the exciting field magnets of the LSM that also serve as the levitation magnets that pull the vehicle up to the LSM stator magnets packs attached to the guideway. Figure 87 shows a side-view cross-section of the LSM with the 3-phase primary winding embedded in the stator core on the guideway and the vehicle's levitation magnets.
The long stators of the LSM located on the guideway form the active track. The reactive forces of propulsion and vehicle levitation act on the stator cores. The supporting structure is required to have enough strength to handle repeated loading of this force, and the stator coils need to be isolated from ground. Dimensions of the stators are determined by the highest performance requirement of the systems.
In order to reduce operational losses and for stability of the power supply system, the long stator of the LSM is separated into a number of sections controlled by the section switches. minimum length between two section switches depends on the required acceleration and length of a train. The operating frequency of the section switches becomes high if a large number of trains are operated on the track each day. ('
Figure 89: Transrapid TR08 vehicle and close-up of propulsion/levitation module containing on-board exciting magnets for LSM
Flux, o, from the exciting magnet interacts with the traveling magnetic wave from the stator to generate vehicle thrust.
The currents in the stator coils must be synchronized with the train's position and velocity. Proper control of the train can only be accomplished by sending information to the converter stations through the use of sensing equipment and signal transmission systems. Because synchronization is essential to the LSM, the sensing and signal transmission system must have high precision and reliability.
The railway substation shown in Figure 91 is connected to the power grid, so its location may be constrained. In some cases it is advantageous for the system operator to own the transmission line from the grid. The power converter station feeds variable-voltage power to the long stator sections through the transmission lines, and controls both the power's frequency and phase as required by the train's position and velocity. This means that the number of converter stations must equal the maximum number of trains possible on the whole track. An increased number of converter stations will be required near train terminals and intermediate stations. Operational voltage of the converter is limited by the maximum voltage level capability of transmission cables, section switches, and stator windings to prevent arcing and electrical breakdown.
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Figure 91: Block diagram of the power circuit for the LSM
7.3.2. Advantages Vehicle drive power is supplied by the long-stator winding attached to the guideway. Because the stator winding and power conditioning equipment is located wayside, the vehicle should be generally lighter. This permits the operation at high-speed (up to 500 kph has been demonstrated) because the vehicle does not bear the weight of the high-power primary propulsion components needed to obtain these speeds, nor does the electric power need to be transferred to the vehicle. The power-rating capability of the motor can be tailored to the requirements of the specific section of route such as regions of high grade or at the station for high acceleration.
The Transrapid and other proposed LSM systems also use the on-board levitation electromagnets (or permanent magnets) as part of the field source for the LSM propulsion. This results in a highly integrated bogie design that reduces vehicle weight and helps reduce the requirements of the levitation control system to mitigate the effects of transverse forces on ride quality. Other systems such as power generation and operation control can be integrated with the drive system
The placement of main power components on the wayside and reduction in vehicle weight results in high acceleration and deceleration capability. However, the utility of the high acceleration is limited by ride comfort, seat-belt operating conditions, and safety requirements. Within these limits for the FTA urban maglev program, both LIM and LSM have the capability to meet the highacceleration requirements, and neither has a particular advantage in terms of the superiority of these three factors.
The electrical-to-mechanical conversion efficiency of LSM is high at the terminals of the guideway motor, but the impedance of the active block length of the motor reduces that value. A detailed analysis conducted for the U.S. Department of Transportation National Maglev Initiative modeled
Colorado Maglev Project Part 3: Comprehensive the Transrapid TRO7 LSM with a lumped-parameter synchronous motor circuit model.(*) This model was benchmarked with data from the Transrapid TR06-11 motor, and the author of that study indicates that the agreement with data was excellent. For the TRO7 with an on-board active length of 45 meter with a relatively-short LSM block section length of 300 meters, the efficiency at the terminals of the LSM immediately below the vehicle is 98% at a vehicle speed of 200 kph in maximum-thrust operating mode. The efficiency at the terminals of the LSM block section is 85%, and at the output of the variable-voltage, variable-frequency converter, the efficiency drops to 62% at the same speed and operating condition. The maximum efficiency at the converter output for this LSM, which was designed for higher speed, is 87% at a speed of 480 kph. However, it should be noted that if the block section length of the active LSM is longer, the efficiency is reduced. 7.3.4. Alternative LSM Design track allowed to the linear motor drive. However, uncertainty of the reliable operation of rubber tires in high speed and of the basis of investment costs, the project was dropped, and RTRI has stopped further study.
7.3.3. Disadvantages One disadvantage of the LSM drive is that it requires data for the exact position of the on-board magnets to ensure that the vehicle is synchronous with the traveling wave generated by the stator winding in the guideway. A very reliable and precise vehicle position and velocity sensing system is essential. This information must be transmitted to the converter station to generate the traveling magnetic field at the appropriate magnitude and frequency.
Compared to the simple reaction rail of the LIM, the active track structure of the LSM is very complicated. It requires continuous installation of stator coils in the guideway and wayside converters to energize each block section of track. This results in many components that must be maintained to assure the safety of the system. The maintenance of proper position of the guideway stator coils is particularly critical so that the proper clearance gap is maintained to the on-board levitation/excitation magnets. Reduction of the normal 1 cm gap can result in significant increase in the vehicle lift force causing the vehicle to "lock-on" to the guideway or impact between the vehicle magnets and the guideway stator. Frequent inspection and maintenance of the guideway coils and stator core is necessary to ensure proper alignment.
There are several operational requirements for the vehicles relative to the guideway. Each block section of the guideway can drive only one vehicle at a time, and that section requires its own converter. The operational density of trains on the route determines the number of converter stations, which implies many converters are necessary for short headway systems. This has particular impact near terminals where the power feeding system becomes complicated and many converters are needed since vehicles are moving slowly, more closely spaced, and switching direction or routes. The vehicle has an LSM motor on both the port and starboard sides, and each of these is powered by independent power supplies at the transitions between stator sections. These supplies must have high reliability for balanced thrust from both sides of the vehicle. The field magnet of LSM is also commonly used for vertical suspension, which means it is operated continuously. This requires a very reliable on-board power supply including batteries. In the event of a malfunction of trackside stators, the riding comfort is significantly deteriorated.
The performance of the transportation system is determined by the configuration of the active guideway, and the system is not adaptable to the change of passenger demand. Vehicles cannot be added easily to accommodate changes outside the original design (although they are easily removed). The LSM must be configured, and the initial investment made to accommodate the highest demand anticipated over the life of the design. For efficient use of capital investment, a very accurate estimate of demand is necessary.
“Technical Assessment of Maglev System Concepts, Final Report by the Government Maglev System Assessment Team," James H. Lever, ed., U.S. Army Corps of Engineers Cold Regions Research and Engineering Laboratory report no. 98-12, October 1998, pp 62.
To permit more flexibility of operation and allow short headways for high-capacity operation, a design has been proposed with very short stator sections. With appropriate design, the operation control system (signaling system) can be integrated with the power feeding system. The stator sections of the Locally Commutated Linear Synchronous Motor (LCLSM) are essentially individual coils, each energized by its own wayside inverter.(40) While this reduction in stator length improves the electrical efficiency at the converter to 95% and increases the power factor, it requires an inverter for each coil (or pair) in the guideway. In a previous proposal of this technology in the U.S. National Maglev Initiative, this required 2400 inverters per kilometer of double guideway. The technical assessment of that proposal by the U.S. Government Maglev Assessment Team (USGMAT) concluded that while the LCLSM offered high efficiency and possibility for very short vehicle headways and operational flexibility, the guideway stator investment cost was "critically dependent upon the high-volume cost reduction (factor of 10)” for the IGBT switch based inverters.
Another important issue with the concept is the potential reliability of the system with such a large number of inverters. The USGMAT report makes reference to the fact that with individuallycontrolled coils, the system could operate in a degraded mode even if a few coils or inverters fail. However, this capability will be highly dependent upon the nature of the failure. The resulting ride quality and operational safety may be significantly affected, and the ability to operate in degraded mode in not at all obvious, particularly in light of the team's assessment that the synthesis of the stator's traveling wave from individually-energized coils was a demanding technical requirement and unproven at that time. Sub-scale testing of this concept has been done that shows thrust can be delivered even with some faulted coils, but it is not clear that a full-scale system with such faults would be necessarily operational, or that any level of operation other than vehicle recovery is desirable.
A concept of this type of linear motor for the maglev railway was proposed by Dr. Matsui of RTRI Japan in late 1960's. (1) It was named as “Linear DC Motor”, because its principle of operation was quite similar with the brushless DC motor. The idea and its characteristics have been reported by Dr. Matsui and his colleague, Mr. Umemori. (2) The primary coils and the H-bridge switches are located along the track. The on-board electromagnet acts as the field magnet of the motor. The on-board magnets also give the lift force to the vehicle, though high current must be fed to the vehicle to have enough levitation performance.
A feasibility study of this type of maglev system was also carried out by a technical committee of the Railway Electrification Association of Japan with the support of former Japan National Railways, and the author (Masada) was a member of that committee. The committee's assessment of the system identified two problems: 1) large and heavy on-board magnets are needed for levitation, and 2) H-bridges with power electronic devices for commutation between ground windings are too expensive and complicated for reliable operation. RTRI has changed the concept of system to solve the first problem with rubber-tire wheels and studied its feasibility for suburban transport in Yokohama as Automated Linear-motor Pneumatic-tire System (ALPS). (3) A report written by Mr. Miki of RTRI shows that the construction costs for the system are about 20% less than a conventional system because of smaller curvature and higher gradient
Ibid., pp 11, 80. K. Matsui et Al., "D.C. Linear Motor Controlled by Thyristors and the Testing Equipment for its High Speed Characteristics", p. 149-154, Linear Electric Machines, IEE Conference Publication No. 120, London, 21-23 October 1974. 42 T. Umemori, et al., “Development of DC Linear Motor – Fundamental construction and feasibility," Paper F78 757-7, and "Development of DC Linear Motor (II) – Research for a ground coil and a field magnet,” Paper F78 756-9, both presented at the IEEE Power Engineering Society Summer Meeting, Los Angeles, California, July 16-21, 1978. A. Miki, "ALPS and its future prospect", Proc. Railway Technology Research Institute Seminar, p.86-96, Tokyo, Nov. 1987.
Dr. Matsui has shifted his interests from the original concept to the Belt type Transit System by Magnet (BTM) people mover to solve the second problem. A rotating magnetic belt equipped along the track adheres on board magnets and propels the vehicle in the original system, analogous to an LSM. It was utilized as a transport system of an International fair 1990 in Osaka. Because it was noisy and expensive, the design was modified to equip the moving belt with permanent magnets arrays on board. The belt adheres to the ferromagnetic rail of the track and propels the vehicle. A small scale practical application has been installed and operated since 2003 as a incline-type people mover, which has a mean gradient of 30° at Katsura-dai near Otsuki about 90 km west of the city center of Tokyo, Japan. M4). While this example is neither a conventional LSM nor LIM, the simplicity and low-cost of the on-board driven propulsion for this low speed system is evident.
Based on the design reviews and experience with this type of system, it is concluded that the locally commutated linear synchronous motor has theoretically interesting characteristics for a maglev or a railway transport, but its realization as a practical system is difficult due to costs and reliability of a large number of switches.
7.4. COMPARISON BETWEEN MOTOR DRIVES
7.4.1. Flexibility to Variable and Uncertain Demand As discussed above, a LIM-driven transit system has a great degree of flexibility to respond to variable or uncertain demand by adjusting the number and size of vehicles on a short-term or long-term basis. The ability to add and move vehicles provides the operator rapid response capability to volatile demand and the recovery from any off-normal shutdown or schedule deviation. If additional power is needed to accommodate an upgrade in the system capacity, the impact to the guideway is almost negligible requiring only the addition of way-side power electrification and conditioning equipment. To meet operational requirements, the train control can also be easily adjusted with little, if any, modification to the civil structures.
The LSM lacks flexibility to change system performance. Replacement of ground facilities is necessary to change system capacity or its operational mode, which is quite similar to building a new system. Its active track and power supply installation must be designed and installed for the highest demand and capacity of the system contemplated during the design phase. This may significantly shorten the useful life of the system or greatly increase the life-cycle costs if actual demand does not follow planned usage.
Line operators may experience off-normal schedule delays, interruptions, or shutdowns due to causes beyond their control or equipment failure. Rapid recovery of scheduled operation is critical to maintaining ridership. The ability of the LIM drive to move and stage vehicles on the guideway with moving block control provides a great amount of flexibility to rapidly restore service. This includes tailoring vehicle configurations for short-term, high-capacity operation to immediately accommodate the high-demand resulting from any unscheduled stoppage or deviation from normal scheduled service. The LSM requires a single vehicle per section of track, and cannot accommodate a surge in service throughput, unless the system was highly underutilized previously. The required movement of a single vehicle on a fixed guideway section greatly limits the flexibility to stage vehicles to respond to off-normal demand profiles or incidents.
"Belt type Transit System by Magnet”, Leaflet of Nihon Densetsu Kogyo, 2000.
In the event of a malfunction of the propulsion motor, the speed of recovery of service is very important. In the case of LIM propulsion, the vehicle is simply moved and replaced. This can be done with the aid of another transit vehicle or special service vehicle. If the vehicle is LSM powered, it is much more likely that the track may need time-intensive repair or replacement of stator winding sections. During that repair and re-qualification testing, the entire track is out of service. Service vehicles for such incidents may need to be independently powered, and may be unable to utilize the guideway structure effectively.
7.4.2. Reliability of Operation Operational reliability of the LSM strongly depends on the detection and signal transmission system for vehicle position and velocity to ensure that the magnetic wave generated in the stator winding is synchronous with the movement of the excitation magnets on the vehicle. Doublyredundant systems are required. Reliability of the LIM in a high-vehicle-density operation of a transportation system is based on existing conventional-rail technologies, and has been well established, for example in the Linear Metro system in Tokyo, Japan.
Although many future transit systems are contemplating driverless operation, for systems where drivers are determined to be necessary, the human factors have been well established for the LIM drives. The operators of conventional railways can easily adapt to the new LIM system using much of their previous experience.
The reliability of the electrical and mechanical components of the linear drive must be evaluated, and it is very important to obtain duration-test data from the designed track to fully qualify the reliability of the drive. This information is compared to corresponding data from previous installations or test tracks to determine the effects of design, fabrication, or installation process modifications. The larger the database of previous applications and lifetime testing of a technology, the higher the confidence will be in a planned system's reliability. The application of LIM drives in steel-wheel transit systems and the historic usage of similar power conditioning equipment in conventional, rotary drive rails systems provides a significant experience base for confident projection of LIM designs to future maglev applications. Although LSM has been significantly evaluated at test tracks, the reliability of active tracks and section switches must be established with duration tests under revenue service conditions. Collection of this data is still in progress, and will not be completed for a few years.
7.4.3. Capital Cost The capital cost for a maglev system is dominated by the cost of the civil structures, including the guideway; the size of the guideway depends on the loadings, including the weight of the vehicles. To obtain an accurate cost comparison between the LIM and LSM propulsion methods, a detailed analysis must be done for a given route and ridership requirements. However, there are features of each drive system than can be identified which have significantly different cost elements.
The weight of the vehicle using the LSM drive is expected to be lighter than one using the LIM since there is little on-board power conditioning equipment. This would, in principle, reduce the cost of the guideway. However, from the design experience for the CMP, the live load is a small part compared to the dead load weight of the structure itself, and the weight of the car does not strongly influence the cost of the guideway. It is also interesting to note that the 24.3 meter long, LIM-driven COL-200 vehicle that carries 103 passengers weighs 44 tonne fully loaded, while the 24.8 meter long, LSM-driven Transrapid vehicle that carries 126 passengers weighs approximately 60 tonnes fully loaded.(09) While the Transrapid vehicle can achieve higher speed, its weight would not decrease if the vehicle were limited to the 200 kph design speed of the COL200.
"High-Tech for Flying on the Ground," Transrapid International technical brochure, 2002.
Colorado Maglev Project Part 3: Comprehensive Page 22
table footnote. Variation in the cost per unit track length is expected due to the different operational, geographic, environmental, and ridership requirements of the individual routes. However, the table shows the cost per unit track length decreases with distance as expected.
Urban and suburban type maglev costs may be closest to the estimates for the Metrorapid system that has 6 stations total and 16 km average distance between stations. This affects the cost of the system and reduces the average speed significantly. A plot of the data as a function of average speed is shown in Figure 92 where a trendline has been added for the LSM data (excluding the value for the Berlin Airport Connection that is much greater than the other data due to tunneling and number of stops). While there is scatter in the data, there is a definite trend for decreasing cost per unit track length as average speed increases. A data point for the FTA Urban Maglev CDOT Project (256 km, 114 kph average speed, double track, 36.7 M$/mile including contingency) has been added for comparison that shows the significantly lower cost for this LIM-driven technology.
Table 7.4-1. Comparison of Investment Costs Between Various Transrapid Applications Distance Avg Velocity Track Investment Costs per Unit Guideway Length Reference System km kph Type MDM/km M €/km M$/km* M$/mile* Number Date Berlin Airport Connection 25 94 double 189 121 194 17 2000 Shanghai Airport Connection 30 222 single 43 69 15 2003 Munich Airport Connection 37 220 double 78.3 50 81 17 2000 42.2 53 85 18 2002 Metrorapid Dusseldorf 78 120 double 93 59 96 17 2000 39.7 50 80 18 2002 Frankfurt-Hahn Airport 116 35 56 17 2000 Berlin-Hamburg 284 233 double 31.4 20 32 16 1994 Gronigen-Hamburg 293 245 double 35.9 23 37 17 2000 • Cost Conversion of DM to Euro using 31 December 1998 irevocably fixed conversion rate of 1.95583 DMEuro adopted by European Monetary Union Member States. Conversion of Euro to US Dollar at current rate of 0.8 ONSD
FTA Urban Maglev Program, CDOT Team report "Final Report Interim," pp. 20, 7Jan04.
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"High-Tech for Flying on the Ground," Transrapid International technical brochure, 2002. P. Holmer, "Faster Than a Speeding Bullet Train," IEEE Spectrum, Aug. 2003, pp. 30-34. "Concept for the financing and private sector operation of the superspeed maglev system Berlin-Hamburg," Magnetschnellbahn Berlin-Hamburg GmbH report, January, 1994. "Magnetschnellbahn Streckenauswahl Vorstudie," Die Bahn report, Berlin, October 15, 2000. H.G. Lindlar, "Machbarkeitsstudie fuer Metrorapid Rein-Ruhr und Transrapid Muenchen," ETR (Eisenbahntechnische Rundschau, Darmstadt: Hestra), vol. 51, no. 5, pp 285-295, 2002. FTA Urban Maglev Program, CDOT Team report "Final Report Interim," pp. 20, 7Jan04.
8.0 CMP WINTERIZATION REQUIREMENTS
This section provides additional detailed winterization data and vehicle requirements for maglev operations in the Colorado 1-70 mountain corridor during winter storm events.
This chapter is divided into three main sections:
1. HSST Transit Operations Experience 2. HSST Winterization Experience and Recommendations 3. Detailed discussion of winterization requirements for Colorado car.
8.1. HSST TRANSIT OPERATIONS EXPERIENCE HSST has extensive experience with their maglev transit system including operation in moderate winter climates. The operational experience in a moderate winter climate provides the data and basis for the winterization requirements for the winter operational conditions that will be confronted in the Colorado Rocky Mountains.
Development of the High Speed Surface Transport (HSST) began in the early 1970s, under the auspices and direction of Japan Airlines in order to introduce a new form of transport (fast, efficient and environmentally friendly) to connect airports with city activity centers. Japan Airlines' objective was to develop a system that could be used in lower speed applications such as in urban areas where tight turns are necessary as well as having higher speed capability in more open areas. The development process has had the same basic principles from the early development process to the current deployment in Nagoya, Japan. The transit vehicles were designed using electro-magnetic suspension (EMS) generating attractive magnetic forces with a U-shaped magnet wrapped around an iron rail creating levitation forces. Linear induction motors provide the propulsion. With the Nagoya, Japan TKL deployment additional aspects of operating in moderate winter climates have been taken into consideration in the overall vehicle development process. The following describes the development process for the HSST vehicle.
Developmental Process 1970-1978 Japan Airlines constructed a 1.3 km (0.8 mile) track and carried out a series of operational experiments with two test vehicles, designated HSST-01 and -02. Following was an operational testing program where prototypes were successfully tested at speeds of up to 308 km/hr (193 mph). Over the next several years, Japan Airlines (HSST) concentrated their efforts on developing a commercial version of the vehicle. Operations The development of the HSST 100-S and 100-L vehicles has gone through an extensive series of passenger-carrying deployments to allow for the proper assessment by the Japan Ministry of Transport prior to issuing a railway business license for commercial operations. In combination, HSST vehicles have carried passengers for over 42 months transporting over 3 million passengers. FTA survey teams have visited the Nagoya, Japan TKL deployment working in conjunction with the FTA Urban Maglev Development Program and declared the CHSST technically capable to be deployed in the United States.
Tsukuba Science Exposition, HSST-03 track length of 350 meters (0.22 miles) vehicle - 50 passengers 610,000 regular passengers transported
Colorado Maglev Project Part 3: Comprehensive Technical Memorandum delivered to Nagoya track for pre-operational performance running.
Mar.-Oct.1989 Yokohama Exposition, HSST-05 track length of 515 meters (0.32 miles) 1.2 million regular passengers transported distance traveled 29,000 km (18,000 miles) Japan Ministry of Transport issued a railway business license for commercial operations
Additional Development Deployment 1991 CHSST Corporation formed by Aichi Prefecture, Nagoya Railroad and HSST Corporation to produce commercial vehicles for deployment.
CHSST constructed 1.6 km (1 mile) track in Nagoya for full-scale commercial operation of HSST's 100-S (short wheel base) and 100-L (long wheel base).
Japan Ministry of Transport (MOT) issues acceptance of the technology confirming no technical deficiencies and enacted laws for public transport use for operational speeds in the Nagoya application up to 100 km/hr (62 mph).
Nagoya Deployment 1999 HSST deployment begins in Aichi Prefecture, Nagoya for a feeder line 9 km (5.6 miles) long with nine stations connecting a terminal of the Nagoya City subway in the eastern section of downtown Nagoya to one of the Aichi Circle Line station. The route includes areas of tight horizontal and vertical curvature, a tunnel section and sections with steep grades (up to 6%). The climate in Nagoya has some moderate winter conditions with light snow and sleet occurring infrequently. The HSST system design was reviewed with winter conditions to determine design adjustments necessary for operations.
Train-set to be deployed on open sections of guideway for preoperational performance running.
8.2. HSST WINTERIZATION EXPERIENCE AND RECOMMENDATIONS CHSST engineers have assessed the Nagoya TKL deployment from the perspective of winter operations conditions and determined the following courses of action to be taken on various subsystems of the HSST system to assure operations during winter conditions.
Guideway impacts from winter operating conditions result in:
a. Disruption of normal vehicle operation due to snow accumulation on reaction plate and skid surface; and, b. Icing of brake surface, where mechanical brakes are applied, reducing the performance of the brake.
Mitigation efforts include:
a. Application of special coating that assists in clearing snow on the reaction plate and skid surface; b. Use snow/ice plow that can remove or scrape snow/ice/frost from rail surface to prevent accumulation during normal train operation; C. Operate trains during all hours including night time in winter storm conditions; d. The specific places where extreme weather conditions are historically observed should be sheltered. The extreme weather conditions include heavy snowfall accumulations, major snow drifting, strong wind gusts or avalanche paths. e. Apply rail heating at braking surface as needed. Rail heating is assessed in detail in Section 8.3 and Appendix 5 to provide the economics and alternatives to heating. f. Use a gas turbine engine driven maintenance servicing car that can produce compressed air to blow snow/frost away and dry braking rail surface. This type of car is useful since heavy maintenance work can be done safely without trolley electric power.
8.2.2. Guideway Equipment Specific guideway equipment will also be impacted by winter conditions including:
a. Power rails may accumulate snow or ice damaging the power collectors and disrupting normal power collection. b. The signal line may accumulate snow or ice that will interfere with the vehicle antenna disrupting normal functions.
Mitigation efforts include:
8.2.2.1. Power Rails Moving the contact surface of the power rail and the collector shoes under the surface of the power rail and installing power rail covers on the rail to prevent snow accumulation on the power rail itself. (See typical cross section of guideway/power rail in Figure 94.)
8.2.2.2. Signal Line For the current speed detection equipment, change the signaling line location from the upper to side surface of girder and install it vertically. Adopt vehicle speed detection equipment that can eliminate belt-wise line on girder beam. Radio wave (Doppler effect) type speed detection equipment is a candidate.
8.2.2.3. Switch The switch mechanism and locations for switches are critical to maintaining headways and safe operations.
Snowfall/ice on guide rail interferes with the switch girder wheel disrupting the girder wheel causing malfunctioning switches. Mitigation efforts include:
Using snow plows at switch locations to remove snow Providing heating equipment along the guide rail Shelter the entire switch and immediate surrounding area In case of power collection from under the surface of the power rail, the trolley line may need a special device such as a flapping mechanism connecting the trolley line at switching.
In-operation or malfunctions of electric/electronic equipment or parts due to cold
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Use parts or standardize specifications using cold weatherproofing and covering. Add heating elements.
8.2.3. Vehicle Japanese transit vehicle manufacturers have experience manufacturing transit vehicles for transit properties where winter operations are prevalent, including Chicago's Metra system and systems in New York State.
In the HSST vehicle there are numerous under-floor equipment arrangements that may be impacted by winter operations. A number of these items are discussed below with potential mitigation techniques cited.
8.2.3.1. Power Collector This includes the power collector where snow and/or ice accumulation on the power collection rail may damage the vehicle power collectors disrupting normal power collection. A potential mitigation to this situation is the installation of additional power collector-like devices that function as snow/ice scrapers to protect the power collector. Additionally the material of the contact shoe should be weatherproof such as a ceramic material.
8.2.3.2. Doors Vehicle doors historically are impacted by cold temperatures, snow and ice buildup causing the door to become inoperative or to malfunction causing a delay in operations. Door problems can be handled through proper heating at the doorsills and around the door operations mechanisms. An additional solution for the door operator mechanisms is to use an electric motor that has a larger initial torque than the conventional air driven mechanisms.
8.2.3.3. Bogie Snow accumulation around module bogies disturbs and alters the smooth and correctly aligned vehicle movement. A number of mitigation measures can be taken including:
1. Application of an ice-proof coating on the bogie structure surface to prevent ice/snow accumulation. 2. If needed, install heating devices. 3. Use snowplows at the leading and rear end module to clear snow from the rail surface. 4. Install shrouds or boots preventing snow/ice intrusion at or around components such as ball bearings of the movable link and linear bearing to guarantee smooth movement.
8.2.3.4. Brake Brake caliper surface icing will prohibit the correct performance of the brakes. This situation can be corrected by providing a heating device at the brake caliper. Additionally, an ice-proof coating can be applied to the surfaces eliminating ice buildup.
Snow accumulation around the brake body can also prohibit smooth brake operation. This situation can be corrected by covering the brake body.
8.2.3.5. Electric/Electronics Equipment Box A potential issue is that equipment becomes inoperative due to snow/water intrusion into equipment boxes. This can be corrected by providing equipment boxes or compartments that are watertight either by using boxes with double packing (sealing) or providing special latch mechanisms. Additionally, sufficient backpressure can be provided through air ducts to prevent water and snow intrusion.
Colorado Maglev Project Part 3: Comprehensive In addition to snow and water intrusion, electric and electronic equipment can become inoperative due to low temperatures. Electronic parts, especially the CPU, are not usually guaranteed below zero degrees Celsius. This situation can be corrected by heating the equipment boxes electrically or through warm air directed through air ducts. cold weather climates.
8.2.3.6. Electric Coupler The electric coupler between vehicles can be impacted through snow, water or ice accumulation causing poor electric conduction on the connector pins. This situation can be corrected by heating the coupler assembly.
8.2.3.7. Pneumatic System Parts There are a number of values, rubber rings and other rubber parts, and water separators that may become inoperative or deteriorate due to cold temperatures and icing. For values a simple solution is the installation of jacket type heaters. For the water separators, installation of heater equipment will resolve this issue, while for rubber parts that may deteriorate, the use of coldresistant rubber parts is appropriate.
8.2.3.8. Hydraulic System Cold temperatures can cause hydraulic system deterioration due to a change of viscosity. The hydraulic system can also be impacted through deterioration of rubber parts through cold temperatures. Change in fluid viscosity can be dealt with by using fluids adequate for cold temperature operations. For rubber parts deterioration, the use of cold-resistant rubber parts will correct this situation.
8.2.3.9. Leveling Equipment Value The leveling value can become inoperative due to cold temperatures or ingestion of snow, water or ice. This can be corrected by installing jacket type heaters to heat the valve or by placing the entire valve into a box.
8.2.3.10. Air Conditioning/Heating and Ventilation Air conditioning and heating systems can become less efficient in winter conditions due to low temperatures and snow/ice ingestion into the air intake. This situation can be mitigated by installing larger capacity equipment for increased air movement. Also snow intrusion can be eliminated by placing a louver-shaped covering at the air intake or installing a centrifuge.
8.2.3.11. Windows Transit vehicle windows in the passenger compartment as well as at the front and back of the train-set can deteriorate due to low temperatures and can fog from temperature differences between the inside and outside of the vehicle. Windows can be double pane, tempered or be manufactured with polycarbonate material. In addition window heaters can be used as defoggers or anti-icing systems can be installed.
8.2.3.12. Horn The vehicle horn can be impacted by icing on vibrating parts or by snow intrusion into the horn assembly. These situations can be corrected by adding a heater for icing and a mesh guard to prevent snow intrusion into the horn assembly.
8.2.3.13. Lubricants and Grease Lubricants and grease can deteriorate in performance due to an increase in viscosity. These situations can be corrected by using lubricants and greases that are specifically manufactured for
8.3. COLORADO WINTER CLIMATE AND SYSTEM WINTERIZATION APPROACH The following sections discuss the winter conditions in which the CMP will operate. Additionally, specific approaches for winterization mitigation actions for specific elements of the system are presented
8.3.1. Corridor Characteristics The characteristics of the CMP corridor in terms of weather conditions and related aspects are presented below.
8.3.1.1. Elevation The Colorado 1-70 mountain corridor is a demanding environment due to the extreme changes in elevation along the 266 km (165 mile) right-of-way beginning at DIA (elevation 1615 m (5300 ft.)] and ending at Eagle County Airport (near Gypsum, Co, elevation 1844 m (6050 ft.)]. The route climbs and descends two mountain passes with elevations between 3251 m (10666 ft.) and 3401 m (11158 ft.). Extreme alpine weather conditions, rockfalls and avalanche potential contribute to the design challenges.
8.3.1.2. Temperature Daily wintertime temperatures can vary along the route by as much as 30°C (54°F). The most extreme seasonal temperatures of 47°C (winter) to 38°C (summer) have been measured at Eagle County Airport. This represents a potential annual 85°C (153°F) temperature differential.
8.3.1.3. Snowfall Snow can fall at rates exceeding 75 mm/hr (3 in/hr) with daily accumulations of over 0.75 m (30 in). On the mountain passes, a snowfall rate of 125 mm/hr (5 in/hr) has been observed to occur about every five years (Atkins, 2003). A snowfall rate of 0.3 m/hr (13 in./hr.) was recorded on Berthoud Pass in 1933 (Judson, 1965). See Figure 95 and Figure 96 for early winter conditions.
Colorado Maglev Project Part 3: Comprehensive
8.3.1.4. Wind Maximum wintertime wind gusts of 50 m/s have been measured at Georgetown Lake within the past three years. Mean daily peak wind speeds are shown in Figure 97.
(Notice that the wind peaks generally occur in the winter and spring months. "South" readings were acquired from a weather station located in Georgetown on top of a residential building.)
Wind data from several ski areas located near the 1-70 mountain corridor has been collected over the past year. However, the wind conditions in Georgetown (and particularly those associated with the Georgetown Lake) are a factor of 2 more severe than that at any of the other locations considered. A potential reason for this phenomenon is explained by considering the photograph provided in Figure 98.
One reason for the severe winds in the Georgetown Lake area can be attributed to the relatively narrow canyons along 1-70 and the venturi effect. It is well known that a fluid in subsonic flow accelerates as it approaches the throat of a nozzle or venturi. The narrow canyons provide the "throat" for flow acceleration. In addition, Georgetown is located at the confluence of two major airflow streams. One canyon seen on the upper left of the photograph descends from the Guanella Pass area. This pass connects the immense high altitude valley area called South Park (to the southwest of Georgetown) with the Clear Creek canyon (to the west and east of Georgetown), along which 1-70 passes. Clear Creek canyon comes down from the upper right in the photograph. You can see 1-70 turning right as it follows this canyon. Occasionally, cold wind falls and is pushed down both of these canyons into Georgetown, developing a mixing layer. The resulting large-scale turbulent flow can have a buffeting effect on over-the-road trucks as is evident from the occasional truck that is overturned in this area. In February 1884, the Georgetown Courier reported that the engine, tender and three passengers cars of a narrow gauge train were overturned by the wind at the same approximate location of today's Georgetown Lake (Georgetown Courier, 1884).
Colorado Maglev Project Part 3: Comprehensive Page 25
Table 8.3-1 Results of the FMEA Analysis. (The top five RPNs are highlighted in bold) Subsystem Severity Likelihood Capability Risk Priority of of Number Occurrence Detection (RPN) 5 105 <50 mm snow depth Guideway/ehicle Interface 8 5 3 120 >50 mm snow depth High Speed Switches 9 5 2 90 Circuit Breakers 9 4 2 72 Power Collection - LIM 8 5 2 80 Power Collection - LSM 6 or 7 2 48 or 56 Snow Removal and 9 4 2 72 Maintenance Cleaning Equipment Auxiliary Heater Systems 6 or 9 4 2 48 or 72 Impacts of Wind (transit 9 4 2 72 system concern) Vehicle Concerns Mechanical Latches 4 or 9 3 2 24 or 54 Motors and Actuators 9 3 2 54 Vehicle Braking Systems 9 54 Vehicle Bogie compartment 10 4 5 200 winter design requirements Station Concerns Environmental Design 5 3 2 Considerations Snow and Ice Removal 6 4 2 48 Auxiliary Heating 2 4 2 16 Requirements
8.3.4. Potential Vehicle Subsystem Solutions from Impacts on the Guideway
8.3.4.1. Vehicle-Guideway Interface
The HSST system incorporates a 14-15 mm gap between the aluminum reaction rail and the bottom surface of the linear induction motor (LIM). This gap is actively maintained by using a proximity sensor located on the bottom side of the rail. Current flowing through the wire wrapped around the levitation magnet is varied thus controlling the strength of the magnetic field attracted to the lower tines of the steel structural rail. A caliper brake located around the outer tine on the bottom portion of the steel rail provides the secondary braking system. Electrical power is collected on one side of the vehicle via the vehicle power collector in sliding contact with the third rail. Page 26
Table 8.3-3 Material cost estimate for winterizing the switches discussed in an earlier Task 12 report. Pivoting High Moving Bending Beam Speed Table Docking Heater Areas (m^2). 1.30 2.47 162.19 119.44 Heater Power Requirements (W) 4019 7665 502794 370275 Heater Cost ($) $1,205 $1,150 $75,419 $55,540 Insulation Cost ($) $69 $67 $4,364 $3,215 Total Material Cost $1,275 $1,216 $79,785 $58,755
Regardless of the actuator used, the bending beam and pivoting high-speed switch would be guided by a steel wheel riding on a steel rail. The wheel and rail assembly would rest on columns raised over 2 m above the ground level. To minimize the impact of snow and ice on this switch guidance system, it is proposed that heaters be used to warm the rail when there is substantial snowfall. The heaters should also be insulated to direct the heat where it is need and therefore, minimize the energy consumption. This is shown schematically in Figure 105 below.
Figure 105: Heater configuration for the switch guidance rails on pivoting and bending beam switches.
Moving table and docking switches would likely be raised with air bearings prior to actuation. It will be important to keep the surface below which the air bearings are acting free of snow and ice. Estimates of the heater area necessary to prevent snow and ice from accumulating on these horizontal surfaces and their associated costs are provided in Table 8.3-3.
In the analysis of switches performed as part of Task 12, it was stated that the pivoting switch can be actuated by a series of three electric motors. With regard to winterization, it is important that these motors be located above the ground and beneath the switch guideway. They should be housed within a vented enclosure. There may be a need to periodically electrically heat the vents to prevent the buildup of snow and ice that would tend to clog the vent.
8.3.4.3. Vehicle braking systems Primary braking system on the HSST system is electromagnetic through pole reversal on the linear induction motors (LIM). Secondary brakes are hydraulically actuated brake calipers that clinch the outer tine of the steel structural rail (see Figure 99). The tertiary braking system is to de-energize the electromagnetic levitation allowing the vehicle to rest on brake shoes mounted between the LIMs. These shoes will contact and thus form a friction surface with the aluminum reaction rail. |
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