Distribution network line single-phase high-resistance grounding fault detection method and device

Abstract

The invention provides a distribution network line single-phase high-resistance grounding fault detection method and device. The fault detection method comprises the steps: S101, respectively acquiring a zero-sequence voltage signal and a zero-sequence current signal according to a three-phase voltage signal and a three-phase current signal; S102, performing wavelet transformation on the zero-sequence voltage signal and the zero-sequence current signal, and obtaining the maximum value and the minimum value of the zero-sequence voltage signal and the zero-sequence current signal obtained afterwavelet transformation within a first preset time period at a first preset frequency; S103, acquiring and recording the ratio of the zero-sequence voltage signal and the ratio of the zero-sequence current signal, and processing a pre-alarm sign according to the ratio of the zero-sequence voltage signal and the ratio of the zero-sequence current signal; S104, judging whether the pre-warning sign meets a preset condition or not, if so, executing S105, and if not, executing S101; and S105, outputting alarm information of the occurrence of a grounding fault. According to the invention, the grounding fault detection accuracy is improved, help is provided for the rapid elimination of the grounding fault, and the safe operation of a system is ensured.

Description

technical field [0001] The invention relates to the field of power system fault detection, in particular to a single-phase high-resistance grounding fault detection method and device for a distribution network line. Background technique [0002] At present, most of my country's distribution network adopts the neutral ungrounded system or the arc-suppression coil grounded system, also known as the small current grounded system. More than 80% of the total. For single-phase ground faults, due to the low-current grounding operation mode of my country's distribution network lines, and the complex and changeable operating conditions of the distribution network system itself, when a single-phase ground fault occurs in the system, it needs to be judged based on the information of multiple collectors Faults, and it is difficult for multiple collectors to keep the signal consistent due to the sequence of signal transmission, often making judgment errors, and it is difficult to quickly ...

AI Technical Summary

Problems solved by technology

For single-phase ground faults, due to the low-current grounding operation mode of my country's distribution network lines, and the complex and changeable operating conditions of the distribution network system itself, when a single-phase ground fault occurs in the system, it needs to be judged based on the information of multiple collectors faults, and it is difficult for multiple collectors to keep the signal consistent due to the sequence of signal transmission, often making judgment errors, and it is difficult to quickly and accurately detect ground faults

However, if the single-phase ground fault cannot be quickly detected and removed, the single-phase ground fault will easily become a multi-point ground short circuit, which will also cause overvoltage in the system, damage the equipment, and destroy the safe operation of the system.

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