Method for locating grounding fault of power distribution network based on multi-sample frequency wavelet character energy conversion

Abstract

The invention relates to a method for locating a grounding fault of a power distribution network based on multi-sample frequency wavelet character energy conversion. The method comprises the following steps of: adopting the time sequences in equal length and at same starting point for performing wavelet conversion on the original data of the sampling values in different sampling frequencies; converting the acquired original character energy values in all the time sequences onto the minimal sampling frequency; and comparing the magnitude of the relative character energy in all the time sequences in a same frequency, thereby realizing the grounding detection and the fault locating. According to the method, the wavelet conversion is adopted for extracting the fault character energy, converting the fault recording signals in different sampling frequencies into the relative character energy in the minimal sampling frequency and then judging the existence of the grounding fault according to the relative character energy and confirming the beginning and ending of the fault.

Description

technical field [0001] The invention belongs to the technical field of distribution automation. Through the conversion of the wavelet characteristic energy in the distribution network ground fault detection, the detection and positioning of the distribution network ground fault under various sampling frequencies are realized, and the fault characteristic energy is extracted by wavelet transform. The fault recording signal is converted to the relative characteristic energy at the lowest sampling frequency, and then according to the relative characteristic energy, it is judged whether there is a fault and the beginning and end of the fault are determined. Background technique [0002] When a single-phase-to-ground fault occurs in the distribution network, there is a wealth of fault information in the transient process, and the transient process is not affected by the grounding mode, so it is of great significance to use transient components for fault detection. By extracting t...

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Problems solved by technology

After the ground fault occurs, it first goes through the transient transition process (1-2 cycles), and then enters the steady state. However, according to the analysis of field recording data, the transient process and the steady state process are not strictly distinguished according to time.

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