Frequency band adaptive acquisition method for distribution network single-phase grounding fault line selection

Abstract

The invention provides a frequency band adaptive acquisition method for distribution network single-phase grounding fault line selection. According to the frequency band adaptive acquisition method, when a single-phase grounding fault occurs on a distribution network, zero-sequence current of each outgoing line can be divided into common forced components under the effect of zero-sequence voltage and free components which are generated by charge and discharge of inductor and capacitor components related to line parameters; common frequencies in the zero-sequence current of each outgoing line and corresponding phases are solved through utilizing a matrix pencil algorithm; the common frequencies are sorted according to a low-to-high order, and the phases are compared in a grouped manner, and a frequency at or below which the phases of the common frequency components of a certain outgoing line are constantly opposite to that of other lines or the phases of the common frequency components of all the outgoing lines are identical is found out until a next frequency does not satisfy the above condition, and the frequency is a frequency band upper limit; and the frequency band lower limit of a grounding system which is grounded through an arc suppression coil is 150Hz, and the frequency band lower limit of other non-direct grounding systems is 0. The method is not affected by factors such as the operating patterns of the distribution network and inaccurate 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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