Method for measuring single phase ground fault distance of distribution network based on Hilbert-huang transform and genetic algorithm

Abstract

The invention discloses a method for measuring single phase ground fault distance of distribution network based on Hilbert-huang transform and genetic algorithm, which comprises the following steps of: based on accurate selection of fault line, using Hilbert-huang transform (HHT) to extract energy distribution characteristics of fault zero sequence current in different frequency bands at different moments; using genetic algorithm, taking fault distance, ground resistor and fault moment as variables, and taking energy distribution matching degree in different frequency bands as fitness function for feature matching of the original fault signals and the fault zero sequence current characteristics under various different fault conditions obtained by Matlab / Simulink simulation; and using the genetic algorithm to automatically search the fault conditions, taking the fault point with the best matched energy distribution as output, and obtaining distance, namely, output fault distance, from the fault point under the fault condition with the best matched fault characteristic to the bus. In this way, a novel method for extracting fault characteristics by using HHT, carrying out fault characteristic matching by using genetic algorithm and realizing measurement of single phase ground fault distance of distribution network is formed, and such method greatly improves accuracy in measurement of single phase ground fault distance of distribution network.

Description

technical field [0001] The invention relates to a distance measuring method for a single-phase grounding fault in a distribution network, in particular to a distance measuring method for a single-phase grounding fault using Hilbert-huang transformation (HHT) to extract transient fault features and genetic algorithm for fault matching. Background technique [0002] The research on fault location of distribution network has always been one of the important topics in power system, and it is also a difficult problem. Especially for the single-phase short-circuit ground fault with the highest probability of occurrence, it has aroused extensive attention of scholars at home and abroad. [0003] At present, the fault location methods of distribution network mainly include impedance analysis method, traveling wave method, injection method and location method based on distribution network automation system information. The impedance method is easily affected by the path impedance, l...

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Problems solved by technology

The impedance method is easily affected by the path impedance, load current and power supply parameters, and may get multiple fault points; the traveling wave distance measurement method is particularly complicated due to the refraction and reflection of the wave impedance at the discontinuous point, and it is difficult to measure the traveling wave at one end of the line. Correctly identify the reflected wave of the fault point; the injection method needs to consider the interference of ferromagnetic resonance, due to ferromagnetic resonance, the overvoltage and overcurrent inside the system will be generated, which will make the distance measurement error; the positioning method based on the distribution network automation system information not only The implementation cost is too high, and this type of algorithm can only locate the corresponding fault section of the distribution network line, but cannot determine the specific line fault location

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