A dc fed rail mass transit system power network solution involves the solving of numerous nonlinear equations. Embedded analysis modules cable constants transmission line. Normally, the trains of a umts requires a dc power supply by means of rectifier ac dc substations, know as traction substations ts. Of course our biggest source, traction power, has the negative return at a near ground potential. Multitrain simulation of dc rail traction power systems. Finally, section 8 is the concluding section where the results and recommendations are provided. Ieee recommended practice for grounding of dc equipment. Since the return path is also part of the supporting structure of trucks wheels and running rails, it would be very hard and dangerous to elevate it well above ground. Study on distribution coefficient of traction return current. Rail transit, earthing, rail potential control, stray currents. Overview of stray current control in dc railway systems. Proper analysis has been done in terms of grounding of power system and equipment.
Traction power substations are customengineered to meet your exact specifications. Define the traction power supply system tps general grounding and bonding require. Washington metropolitan area transit authority wmata final report. In most of the older traction power systems, the rails were not insulated from the ground, and direct connections between the negative busses of substations and the earth were established. A central location will be needed to supervise the power system. Study on distribution coefficient of traction return. Traction power electrification system investigation report washington metropolitan area transit authority. Core tools allow you to quickly and easily build 3phase and 1phase ac and dc network oneline diagrams with unlimited buses and elements including detailed instrumentation and grounding components. Building mechanical system building ac dc service two battery banks two dc distribution panel one circuit per breaker from. Generic protective relay schemes commonly used in the dc equipment enclosure grounding are shown.
At present there are no recommended guidelines or industry standards that cover dc traction power system grounding. System description a dc traction power system mainly consists of recti. Dev paul pe aecom 2101 webster street, oakland, ca 94612 dev. Traction power substation tpss that converts commercial alternating current electricity into the direct current power used by the light rail vehicles. Dc traction power supply system, to meet to your requirements, and to optimize energy. Ieee trialuse recommended practice for grounding of dc equipment enclosures in traction power distribution facilities ieee 1653. Reversed diode earthing scheme in dc traction power system. Multitrain simulation of dc rail traction power systems with. Evaluation of rail potential based on power distribution in dc. If you continue browsing the site, you agree to the use of cookies on this website. The system grounding arrangement is determined by the grounding of the power source. Theory of power distribution contact, catenary and third rail 5. Thus, the electrical resistance of an earthing system must be low enough to. How effective are automatic grounding devices at the.
The decision whether to earth the positive or the negative pole shall be based upon operational circumstances on site or other considerations. Simulation program a dc fed rail mass transit system power network solution involves solving of numerous nonlinear equations. When powell introduced the pcr concept in 1968, it was an industry first. In the majorityof older traction power systems, the rails were not insulated from the ground, and direct. For the step potential circuit, we have two feet in series, the contact resistance r1 is, therefore, equal to 6. Dc traction power system grounding request pdf researchgate. Contact powell today and let us help you with your solution. First, the human body electrical circuit model is developed, and tolerable step and touch potentials derived from ieee standard 80 are defined.
A railway electrification system supplies electric power to railway trains and trams without an onboard prime mover or local fuel supply. The dc system feeds catenaries of tramways or the third rail of metros, for example. Grounding and bonding of exposed metals is necessary to protect the public from electrical hazards, as well as insuring that there is no interference with the signals and communications systems. Such systems are called directly connected earth systems 1. How effective are automatic grounding devices at the floating. Federal transit administration december 9, 2016 8 new insulators that can be removed for cleaning and then reinstalled. A traction network or traction power network is an electricity grid for the supply of electrified rail networks. An iterative solution of sparse matrixes whose sizes depend on length of line and selected.
This memorandum presents data relating to the design of the traction electrification system grounding and bonding requirements that must be satisfied. The same system was used for milans earliest underground line, milan metros line 1, whose more. Principles of electrical grounding john pfeiffer, p. Multitrain simulation of dc rail traction power systems with regenerative braking m. Sakis meliopoulos slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. A traction substation, traction current converter plant or traction power substation tpss is an electrical substation that converts electric power from the form provided by the electrical power industry for public utility service to an appropriate voltage, current type and frequency to supply railways, trams streetcars or trolleybuses with traction current. A dc fed rail mass transit system power network solution involves the solving of numerous nonlinear. Pdf reversed diode earthing scheme in dc traction power system. Theory, operation and maintenance of substations 6. Nov 30, 2015 the electric traction system is the most efficient of all other traction system such as steam and internal combustion ic engine type systems. California highspeed train project traction electrification system rqmts. Today, this is usually done by semiconductor rectifiers after stepping down the voltage from the utility supply. Electric railways use either electric locomotives hauling passengers or freight in separate cars, electric multiple units passenger cars with their own motors or both. Pdf overview of stray current control in dc railway systems.
Track 8 technical forum traction power 1 how effective are automatic grounding devices at the floating negative rail system of a dc powered rail transit system. Chapter 11 transit traction power track design handbook. Traction power cables will be measured for payment as a lump sum unit. Power system modelling for urban massive transportation systems. Understand the fundamentals of traction power substation, distribution system and overhead contact system design, construction, and operation. Traction return current system consists of the rail, the protective wire pw and the integrated grounding line igl. The design of the power supply network of dc electri ed transit railways is of great importance and requires the use of simulation models. Controllingrailpotentialofdcsuppliedrail traction systems. For the connectivity of catenaries and running rails in the whole line, all the trains and traction substations are in parallel. Use of elevated and portions of subway structures as part of the negative return system and connections between aban doned streetcar rails and the negative buses of substations. The power supply network is composed of a high voltage network fed with ac linked to a traction network fed with dc by traction substations. The topic of system grounding is extremely important, as it affects the susceptibility of the system to voltage transients, determines the types of loads the system can accommodate, and helps to determine the system protection requirements. A dc fed rail mass transit system power network solution involves the solving of. Electricity is typically generated in large and relatively efficient generating.
A dc traction power system mainly consists of rectifier units. The return current passes through mother earth as well as rails in such traction systems. Controlling rail potential of dc supplied rail traction systems. Ac and dc power, test meter reading, and computers. Unless the traffic to be handled is heavy, electric traction becomes uneconomical. Power system modelling for urban massive transportation. It offers several benefits over other systems, including quick start and stop, very efficient, pollutionfree, easy to handle and easy speed control. Dc power system training the purpose of this presentation is to give an introduction to dc power systems and dc power fundamentals. Dc traction power system grounding semantic scholar. Power failure for few minutes can cause traffic dislocation for hours. Comprehensive overview of train operations, safety and history of traction power systems 2.
Design of power supply system in dc electrified transit. An analysis of equipment grounding, system grounding, and their relationships to achieve optimized equipment and personal safety is derived. An analysis of equipment grounding, system grounding and their relationships to achieve optimized equipment and personal safety is derived. Traction power electrification system investigation wmata. In the majorityof older traction power systems, the rails were not insulated from the ground, and direct connections between the negative busses of substations and the earth were established. Reversed diode earthing scheme in dc traction power system m. The dc system is quite simple but it requires thick cables and short distances between feeder stations because of the high currents required.
Operational and safety considerations for light rail dc. Savings made possible by energyefficient, heavyduty traction power. The dc voltage is selected according to the system. Politecnico di torino porto institutional repository. Traction electrification system requirements for grounding and. Grounding points within the system, such as at yards, maintenance facilities, and traction power substations. Learn about traction power load flow simulation methods, input requirements and available software for ac and dc traction power systems. A dc fed rail mass transit system power network solution.
Paul in 8 explains the realtime methods applied in north america. To illustrate the basic components affecting the levels of stray currents generated by a dc traction power system, a simple radial feed circuit model is shown in figure 2. Dc power system slideshare uses cookies to improve functionality and performance, and to. Most of these systems are fed by direct current dc. This model assumes that the resistance of the ocs to ground is very high and there is no coupling between the positive circuit and earth.
Evaluation of rail potential based on power distribution in. The installation of a separate traction network generally is done only if the railway in question uses alternating current ac with a frequency lower than that of the national grid, such as in germany, austria and switzerland. Traction power electrification system investigation. Pdf reversed diode earthing scheme in dc traction power. This technical article shows earthing of a specific pole of a twowire dc distribution systems. As one of the worlds leading suppliers of electrotechnical plants and innovative technology partner to all major rail operators, we offer you all services from one source and enable you to tap a lot of potential savings. Railway transportation systems for a comfortable future. Obtain an introduction to traction power wayside energy. Aug 23, 2016 power system grounding and transients. Evaluation of rail potential based on power distribution. Ieee trialuse recommended practice for grounding of dc. Specialized traction power tools and test equipment 4. Electric power shall be supplied to the vehicles from the wayside contact rail system installed parallel to each track.
Dc traction power system grounding ieee conference. Normally, the trains of a umts requires a dc power supply by means of rectifier acdc substations, know as traction substations ts. The installation of a separate traction network generally is done only if the railway in question uses alternating current ac with a frequency lower than that of the national grid, such as in germany, austria and switzerland alternatively, the threephase alternating current of. Envilinetm vld voltage limiting device for dc rail transportation. It plays an important role in traction power supply system of highspeed railway. A schematic of a dc traction power system is shown in figure1.
The most vital factor against electric traction is the initial high cost of laying out overhead electric supply system. This is a discussion of the basic principles behind grounding systems and how grounding is related to safety and the effective operation of circuit protection devices such as fuses and circuit breakers. Traction power substation tps grounding detection of. The design of the return current network is critical to keep the safe and reliable operation of the traction power supply system. The railway system division, in its commitment to future progress, has consistently achieved technological breakthroughs on three systems that are shaping the future worldwide. Traction power security related procedures and regulatory agency authority.
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