PROTECTION METHOD FOR POWER DISTRIBUTION SYSTEM PROVIDED WITH REACTIVE POWER COMPENSATING FUNCTION

摘要

PROBLEM TO BE SOLVED: To draw apart a semiconductor power converter at high speed from the system by blocking the gate of the semiconductor device, with the semiconductor power converter connected to the system. ;SOLUTION: The condition of the system is monitored at all times, and if an accident occurs in the system and an accident signal is inputted from a detector, the gate of the semiconductor device of a semiconductor power converter is blocked. At this point, the breaker does not break the line. Next, if the system accident vanishes, and a detector detects the recovery from the system accident, this method waits for the output of the system frequency to become stable. The judgment on whether the output of the system frequency detector is stabilized or not is performed from the transition of the result, and when the system frequency is stabilized, a DC capacitor is charged, and the gate block is released. Then, a semiconductor power converter is operated normally. As a result, the semiconductor power converter can be drawn apart from the system at higher speed than conventional one, and the abnormal current caused by the delay of the break can be prevented.;COPYRIGHT: (C)1997,JPO