| 摘要 |
PURPOSE:To suppress overvoltage at the time of overload interruption by transferring energy stored in a filter and a capacitor, installed in two AC systems linked through a converter and an inverter, to DC side and then opening a circuit breaker while dissipating thus transferred energy. CONSTITUTION:Two AC systems 100, 200 are connected through HPFs 12, 22, reactive power compensating capacitors 13, 23 and linking transformers 11, 21 with a converter 10 and an inverter 20, respectively, which are linked through a DC system 300 comprising coils 28, 28' and a resistor 29. When an inverter side controller 31 receives a load interruption command 201 from an overvoltage detector 25 or an emergency interruption command 202 from an operation command board 27, converter control angle is shifted from 120-160 deg. to within the operating region of the converter, i.e., 90 deg., thus making transfer to bypass pair operation. Energy stored in the HPF 22 and the capacitor 23 is converted and dissipated through the resistor 29 in the DC system 300. Consequently, overvoltage is suppressed upon opening of a load circuit breaker 24. |
