Thyristor controlled two-stage magnetic-valve reactor for dynamic VAr-compensation in electric railway power supply systems

The electrification of railway systems is becoming more prevalent throughout the world. The implementation of adjustable speed drives in conjunction with the mobile nature of the trains presents a case where harmonic content varies with time and location along the power supply. Advanced systems implement power factor correction on the rail car system. Existing systems require expensive conversions to accomplish this. A variable saturable reactor is presented here that provides a more economical approach to add power factor correction to existing rail systems. The system includes structure modifications to limit hysteresis and skin effect losses. A 27.5 kV, 2400 kVA system is constructed and tested to confirm the operation of the system.