Abstract: The present invention relates to a differential protection method for bridge circuit in current converter control system, including the steps of: 1). obtaining sample values of the three-phase current for the current converter control system at AC side thereof, and calculating the absolute value of each sampling value respectively; 2). calculating a value of current at the AC side of the current converter control system; and 3). determining whether to perform a relay protection for the current converter control system according to the value current at the AC side of the current converter control system. The method of the present invention provided, is fast, convenient, and with a small amount of calculation. The current converter control system determines whether to perform a relay protection in a short time. Also it reduces the possibility that the equipment burned because of cannot break the circuit in time.

Abstract: The invention relates to rapid online diagnosis method of high-power rectifier open-circuit fault, including: 1) collecting actual output direct current value id(t0) and three phase input electric current instantaneous values ia(t0), ib(t0) and ic(t0) of rectifier at t0 moment, and calculating theoretical output direct current value id? of the rectifier according to ia(t0), ib(t0) and ic(t0); 2) comparing id? (t0) and id(t0), when id? (t0) is not more than k1×id(t0), comparing absolute value of maximal three phase input electric current instantaneous value and pre-set threshold value A1, if the maximal three phase input electric current instantaneous value is not less than A1, the rectifier appears open-circuit fault.

Abstract: The present invention relates to a differential protection method for bridge circuit in current converter control system, including the steps of: 1). obtaining sample values of the three-phase current for the current converter control system at AC side thereof, and calculating the absolute value of each sampling value respectively; 2). calculating a value of current at the AC side of the current converter control system; and 3). determining whether to perform a relay protection for the current converter control system according to the value current at the AC side of the current converter control system. The method of the present invention provided is fast, convenient, and with a small amount of calculation. The current converter control system determines whether to perform a relay protection in a short time. Also it reduces the possibility that the equipment burned because of cannot break the circuit in time.