Feature extraction method of weak transient zero-sequence current fault based on particle swarm optimization

Abstract

The invention relates to a weak transient zero sequence current fault feature extraction method based on PSO (Particle Swarm Optimization). The method comprises the steps: firstly setting a potential function parameter as an optimization object, and forming a group through random initialization particles; secondly carrying out the feature extraction of a weak transient zero sequence current through a variable scale bistable state system, and calculating a cross correlation coefficient between an initial current and the current; thirdly taking the maximization of the cross correlation coefficient as a measurement rule of the detection effect of the transient zero sequence current and the basis for parameter optimization selection, and updating particle position and flying speed according to a fitness value; finally stopping updating and outputting an optimal parameter when the number of evolution times reaches a maximum threshold value, and carrying out the feature extraction of the transient zero sequence current under the condition: completing the fault feature extraction if the cross correlation coefficient is greater than 0.85; or else, carrying out optimization again till the cross correlation coefficient is greater than 0.85, which indicates that the fault feature extraction is completed.

Description

technical field [0001] The invention relates to a weak transient zero-sequence current fault feature extraction method based on particle swarm optimization, and belongs to the field of fault line selection of distribution network of power system. Background technique [0002] The fault line selection of the distribution network has the following difficulties and problems: 1) The fault characteristics of the signal are not obvious: after a single-phase ground fault, the steady-state current is generally less than 30A or even only a few A. In addition, the complex structure of the distribution network sometimes leads to fault characteristics Not obvious, although the fault transient zero-sequence current signal is larger than the steady-state zero-sequence current signal, but the duration is short, and sometimes it is difficult to detect; It will also change frequently, and the harmonic current and distributed capacitance current of its line will also change accordingly. In a...

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Problems solved by technology

[0002] The fault line selection of the distribution network has the following difficulties and problems: 1) The fault characteristics of the signal are not obvious: after a single-phase ground fault, the steady-state current is generally less than 30A or even only a few A. In addition, the complex structure of the distribution network sometimes leads to fault characteristics Not obvious, although the fault transient zero-sequence current signal is larger than the steady-state zero-sequence current signal, but the duration is short, and sometimes it is difficult to detect; It will also change frequently, and the harmonic current and distributed capacitive current of its line will also change accordingly.

However, the existing literature only selects the potential function parameters based on experience, which may lead to inaccurate characteristic signals extracted by stochastic resonance, which greatly affects the application effect of stochastic resonance

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