Self-adaptive line selection method for single-phase earth fault of resonant earthed system

Abstract

Provided is a self-adaptive line selection method for a single-phase earth fault of a resonant earthed system. The self-adaptive line selection method for the single-phase earth fault of the resonant earthed system comprises the steps that when zero-sequence voltage of the system is greater than setting voltage, a fault line selection device is started and records bus zero-sequence voltage and zero-sequence currents of circuits before the fault and after the fault; atomic decomposition improved based on a PSO is carried out on the bus zero-sequence voltage, time of occurrence of the fault is determined, preprocessing is carried out on the collected zero-sequence currents of the circuits based on the time of occurrence of the fault to obtain transient state zero-sequence currents of two power frequency cycles, then the atomic decomposition improved based on the PSO is carried out on the transient state zero-sequence currents, and an optimal matched atom representing a transient state free oscillation component and a decaying direct current component of the transient state zero-sequence current of each circuit is obtained; corresponding characteristic information of the optimal matched atoms is extracted; according to the size of an energy entropy scaling factor, a single-phase earth fault occurrence mode is determined, and self-adaptive fault line selection is carried out according to the mode.

Description

technical field [0001] The invention relates to the field of power distribution technology, in particular to an adaptive fault line selection method for a single-phase ground fault in a resonant ground system. Background technique [0002] Most of the medium and low voltage distribution networks in my country adopt the resonant grounding system grounded by the arc suppressing coil. After a single-phase ground fault, the system is easy to develop into multi-point ground short circuit and phase-to-phase short circuit, which makes the accident continue to expand. Therefore, how to quickly and accurately select the fault line to the power grid Safe and stable operation is of great significance. Due to the weak fault current and the randomness of fault conditions, there has been a lack of accurate and reliable fault line selection methods. At present, the fault line selection method based on transient quantities is insufficient for the processing and analysis of non-stationary fa...

AI Technical Summary

Problems solved by technology

[0003] The present invention mainly solves the problem that the existing fault line selection method based on transient quantities cannot accurately and effectively extract the fault transient characteristics, and lacks a high-sensitivity line selection algorithm; through the improved atomic decomposition method, the single-phase grounding of the resonant system can be effectively identified Amplitude, attenuation coefficient, frequency, phase angle, start and end time of transient component after fault

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