Static power supply for DC 1500V transit system

Chopper or PWM inverter controlled electric cars have evolved out of a long history of electric railways. However, silicon rectifiers and high speed circuit breakers have been dominant in the common DC substations. The authors summarize the modern DC substation equipment delivered to the Transportation Bureau of Sapporo City Japan. Then, the revenue operation field data analyses and the short-circuit fault test results are presented. Emphases are on the GTO circuit breaker and the digital ΔI relay aspects, where ΔI gives current variation profile on a given feeder