Showing papers on "Traction substation published in 1990"

Introduction of static frequency converters on SEPTA's 25 Hz commuter rail system

Abstract: A Southeastern Pennsylvania Transportation Authority (SEPTA) project to replace its 1928-vintage rotary converters and one of its converter stations with static frequency converters (SFCs) is described. An examination is made of the development of this project, including the rationale for maintaining a 25 Hz traction power system. The specific emphasis is on the power factor control and harmonic distortion on the utility company's 60 Hz system. The negotiations with the utility company to connect the first SFC to the existing 13.2 kV service and to provide a 230 kV service for the addition of two more SFCs are also discussed. >

Parallel computer simulation of autotransformer-fed AC traction networks

Abstract: Simulation of electrical conditions in power lines and rails in an on-line mode in AC and DC electrified railways is necessary for effective engineering design. A description is given of the use of a parallel computer to simulate voltages along an autotransformer-fed AC railway. The algorithm, based on the solution of algebraic equations for a single train, produces a faster-than-real-time continuous display of the catenary and rail voltages, with a historical record of train voltage as the train moves along the section. The simulation implemented enables parametric analyses to be made to optimize the power feeding, and shows that operation with constant current, rather than constant power, leads to better regulation of catenary voltage. >

High power factor control system in multilevel converters for AC heavy traction drives

Abstract: A quasi-zero reactive power demand which is mandatory in single-phase AC (25 kV/50 Hz) traction systems is considered. Multilevel converter structures and high-performance control techniques have been developed to fulfil this goal in AC heavy traction drives. The tasks of the three level rectifier are described in detail. The current control logic is particularly suitable for applications to multilevel bridges. Advantages deriving from the use of a medium-voltage converter with three different DC potentials are discussed. Digital simulation performed using the general-purpose electromagnetic transients program made it possible to verify the effectiveness of the regulating techniques on the whole system. By controlling converters suitably, the reactive power flowing was reduced to quasi-zero values having a constant voltage on the DC-link and minimizing the harmonic content of the line current in every load condition. Another regulation technique was studied to balance the voltage on condensers which, acting exclusively on the rectifier and not using dissipating techniques or raising the device switching frequency, manage to keep the unbalance DV within a prefixed band. >

Electrical traction equipment, in particular for vehicles for public transport

Abstract: An equipment for electrical traction, in particular for vehicles for public transport equipped with power feed by means of an overhead electrical line (i e., a trolley wire), which electrical traction equipment, when a pre-fixed trolley-wire voltage is reached, is powered by an accumulator battery associated with a battery-charging static converter, wherein said accumulator battery is recharched during the normal traveling of the vehicle and is furthermore capable of feeding the auxiliary electrical units of the same vehicle.

System considerations for heavy haul diesel-electric locomotives with three phase traction motors

Abstract: A locomotive transmission study has been performed to determine the requirements and design of new three-phase traction drive components for independent bogie control on a six-axle freight locomotive. System considerations that affect locomotive high tractive effort capability and component ratings were investigated using computer models of the traction drive components. These include traction motor load sharing due to wheel-rail friction creep conditions, bogie weight shift, motor torque-speed characteristics, and wheel-diameter variations. The methodology, results and conclusions of the study are presented in detail. >