A frequency band adaptive acquisition method for single-phase ground fault line selection in distribution network

Abstract

The invention provides a frequency band self-adaptive acquisition method for single-phase grounding line selection of a distribution network. When a single-phase ground fault occurs in the distribution network, the zero-sequence current of each outgoing line can be divided into a common mandatory component under the action of zero-sequence voltage and a free component generated by the charging and discharging of inductive and capacitive elements related to the parameters of the line itself. The common frequency and corresponding phase of the zero-sequence current of each outgoing line are solved by using the matrix beam algorithm. Sort the common frequencies from small to large and perform a phase group ratio to find the frequency so that the phase of each common frequency component of a certain outgoing line is always opposite to that of other lines or the common frequency components of all outgoing lines are always in the same phase until the next frequency No longer satisfied, this frequency is the upper band limit. The lower limit of the frequency band of the arc-suppression coil grounding system is 150Hz, and the lower limit of the frequency band of other indirect grounding systems is 0. This method is not affected by the operation mode of the distribution network and the imprecise line parameters.

Description

technical field [0001] The invention relates to a new method for relay protection of an electric power system, in particular to a method for adaptively acquiring frequency bands for line selection for single-phase grounding faults in a distribution network based on a matrix bundle algorithm. Background technique [0002] The problem of line selection for single-phase ground faults in low-current grounding systems has always been a hot and difficult research point, and the current mainstream is the line selection method based on transient information. These transient methods are mainly divided into two categories: 1) Line selection methods based on the amplitude and phase relationship between the transient zero-sequence voltage and each outgoing zero-sequence current in the characteristic frequency band; 2) Selection methods based on other transient characteristics line method. When a single-phase ground fault occurs in a low-current grounding system, the most basic fault fe...

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Problems solved by technology

[0004] The purpose of the present invention is to propose an adaptive acquisition method for the line selection frequency band of a single-phase ground fault in a small current grounding system that is not affected by the operation mode and inaccurate line parameters, so as to solve the problem caused by the inaccurate frequency band selection of the traditional line selection method. Insufficient sensitivity and criterion failure of

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