Method for positioning stator single-phase grounding fault of large salient-pole generator

Abstract

The invention relates to a method for positioning a stator single-phase grounding fault of a large salient-pole generator. The method comprises the steps of a, measuring voltages of three phases and zero sequence voltage of a fault generator; b, comparing the amplitude of the voltages of the three phases, and judging the phase with the lowest voltage to be a fault phase; c, calculating the potential of the fault phase by using the voltages of the three phases of the generator; d, calculating the abrupt change amount of the zero sequence voltage, and calculating a phase angle between the abrupt change amount of the zero sequence voltage and the potential of the fault phase; e, calculating grounding resistance of a fault point; and f, determining the position of the fault point by using the grounding resistance of the fault point and the abrupt change amount of the zero sequence voltage. According to the invention, the grounding resistance of the fault point is calculated by using phase characteristics of the zero sequence voltage, and thus the position of the fault point is determined. The method can realize accurate positioning for a stator single-phase grounding fault of the large salient-pole generator in various neutral point grounding modes, and reliable reference information can be provided for fast maintenance for the fault. In addition, the method is also applicable to units which are not equipped with injection type protection, the equipment investment is not required to be increased, and the application range is wide.

Description

technical field [0001] The invention relates to a method for accurately locating a single-phase grounding fault point of a stator of a large salient pole generator, and belongs to the technical field of generators. Background technique [0002] Large-scale salient pole generators have large distributed capacitance to ground, and single-phase ground faults in stator windings may cause stator core burns or develop into more serious faults. Accurate positioning of the stator single-phase ground fault is helpful to expand the protection function and provide reference information for rapid fault repair. [0003] At present, many scholars have studied the location method of single-phase ground fault of stator of large salient pole generator, and obtained certain research results. For example, the fault location method based on the zero-sequence voltage amplitude is greatly affected by the operation mode of the neutral point and the transition resistance of the ground point, and c...

AI Technical Summary

Problems solved by technology

For example, the fault location method based on the zero-sequence voltage amplitude is greatly affected by the operation mode of the neutral point and the transition resistance of the ground point, and cannot achieve accurate fault location; Dang Xiaoqiang, Liu Junyong, Yang Ke, etc. use the traveling wave signal Realize the location of stator single-phase ground fault, but it is difficult to measure the traveling wave signal, and the positioning accuracy is greatly affected by the fault time and the transition resistance of the fault point; Bi Daqiang, Wang Xiangheng, Li Dejia, etc. use the injected stator To realize fault location, this method first uses the injection signal to calculate the grounding resistance, and then calculates the location of the fault point according to the zero-sequence voltage amplitude.

[0004] In short, most of the existing stator single-phase ground fault location methods for large salient pole generators only consider the zero-sequence voltage amplitude component, ignoring the change of phase characteristics after the fault. further research

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