Fault phase selection method based on current break variable

Abstract

The invention relates to a fault phase selection method based on a current break variable, which belongs to the technical field of fault judgment of a power system and constructs a fault phase selection coefficient by use of the current break variable to realize selection of the fault type and fault phase. The method comprises the following steps of: constructing a fault phase selection coefficient by use of the proportional relationship between the fault current of one phase and the difference between the fault current of other two phases measured by a protection device of a high-voltage line; and then analyzing the different characteristics of the coefficient in various fault conditions to realize fault phase selection of the power system. The method can accurately identify the fault phase within a cyclic wave after the fault occurs, has relatively high sensitivity to various types of faults, is not influenced by the fault position, transition resistance and load current, and has relatively high reliability and good selectivity; and meanwhile, the method has enough sensitivity to the fault phase selection on the weak power side.

Description

technical field [0001] The invention belongs to the technical field of electric power systems, and more specifically relates to a fault phase selection method based on current mutations to construct fault phase-specific selection coefficients by using current mutations to select fault types and fault phases. Background technique [0002] The relay protection device of high-voltage transmission line basically uses current differential protection and distance protection as double main protection, uses three-stage distance protection as backup protection and installs automatic reclosing device. The correct action of the distance protection element and the automatic reclosing device is based on the correct phase selection. The wrong phase selection result will lead to the misoperation of the distance protection and the false closing of the automatic reclosing device, which is very likely to affect the safe and stable operation of the power system. pose a serious threat. [0003...

AI Technical Summary

Problems solved by technology

Generalized impedance mutation phase selection has high sensitivity on both strong and weak power sources, and can better identify single-phase faults and two-phase faults, but it is slightly insufficient in phase selection for three-phase faults

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