Power distribution network fault step type line section method based on spectral kurtosis relative energy entropies

Abstract

The invention relates to a power distribution network fault step type line section method based on spectral kurtosis relative energy entropies. According to the method, when a fault occurs, a first step begins, whether the ratio between a head-wave extremum and a half-wave extremum of the transient state zero-sequence current of adjacent lines is larger than 0 constantly is calculated, if yes, a bus has a fault; if not, the second steps begins for judgment, the spectral kurtosis relative energy entropies of all branch lines are solved, an entropy multiple is calculated, and when the entropy multiple is larger than or equal to a critical value, the line with the largest relative energy entropy in the overhead lines is the fault line; when the entropy multiple is smaller than the critical value, the third step begins, and the line with the largest relative energy entropy in cable lines and a cable-line mixed lines is the fault line. The theoretical analysis and the simulation result show that the method is high in line section accuracy, wide in application range and high in anti-noise capacity.

Description

technical field [0001] The invention relates to a stepwise line selection method for distribution network faults based on spectral kurtosis relative energy entropy, and belongs to the technical field of power system fault line selection. Background technique [0002] At present, the problem of fault line selection in the distribution network has not been well resolved. When a single-phase-to-ground fault occurs, the characteristics of the transient signal are abundant, which makes the analysis method based on the transient signal widely concerned. The commonly used transient signal fault analysis methods include: transient energy method, S transform, and Prony algorithm. , correlation analysis method, empirical mode decomposition method, etc. [0003] Using the transient energy method for fault line selection has a good line selection effect in the event of a low-resistance grounding fault. misjudgment. The S-transform has good time-frequency characteristics, but the amou...

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Problems solved by technology

[0002] At present, the problem of fault line selection in distribution network has not been well solved.

The correlation analysis method can realize fault line selection, but when a small-angle fault occurs, the similarity of the transient zero-sequence current flowing through the sound cable and the sound overhead line becomes worse. At this time, the accuracy of the line selection method based on correlation analysis is difficult. ensure

The empirical mode decomposition method has obvious advantages in the processing of nonlinear and non-stationary signals. It can decompose the intrinsic mode functions that characterize each characteristic component, but it may cause mode aliasing during the decomposition process.

[0004] Although scholars have proposed a variety of methods in the time-frequency domain to solve the problem of distribution network fault line selection, the effect of line selection is not ideal. Therefore, further research is needed for distribution network fault line selection.

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