FAULT DETECTOR OF VOLTAGE-TYPE SELF-EXCITED CONVERTER

摘要

PURPOSE:To provide the fault detector of a voltage type self-excited converter which can detect a fault such as an arm short-circuit, an arm external short- circuit or a short-circuit between AC power lines at a high speed with a simple circuit construction and with which the voltage-type self-excited converter can be protected without preparing unnecessarily large anode reactor and self- extinguishing element. CONSTITUTION:Arms to which a same AC bus line 1A is connected consist of GTO's 2A and 2B. A first detecting means (composed of a bias detector 19A and a reversing circuit 20A) which detects the continity state of one of the GTO's 2A and 2B of which the arms consist and a second detecting means (composed of a snubber discharge detector 18B) which detects the discharge of a snubber capacitor 5B which is connected in parallel to the other of the GTO's 2A and 2B of which the arms to which the same bus line 1A is connected consist. Further, logic circuits 13A and 13B which outputs signals when the logical multiplies of the detection signals of the first and second detecting means are obtained as the fault detection signals of a converter are provided.