A distribution network ground fault identification method, device and equipment

Abstract

The invention discloses a distribution network grounding fault identification method, device and equipment. The method first establishes that a small current signal with the same amplitude and frequency conversion is injected from the neutral point of the distribution network, and the voltage signal fed back is measured through a voltage transformer, thereby Calculate the conductance and capacitance to ground of the distribution network, and then use the conductance to ground and capacitance to ground to calculate the incremental damping rate at each frequency, and then calculate the incremental damping rate generated by the fault transition resistance and superimpose Faults are carried out according to preset criteria to achieve effective amplification of fault characteristic quantities, and at the same time greatly reduce the impact of interference, thereby effectively identifying high-resistance grounding faults. The invention solves the problem of difficult identification of high-resistance ground faults in a resonant ground distribution network, can highlight the characteristics of ground faults, has high anti-noise ability, and greatly improves the identification ability of high-resistance ground faults.

Description

technical field [0001] The invention belongs to the field of detection of ground faults in distribution networks, and in particular relates to a method, device and equipment for identifying ground faults in distribution networks based on multi-frequency incremental damping rate superposition. Background technique [0002] The distribution network goes deep into the user terminal, the operating conditions are complex and changeable, and faults are extremely prone to occur, 80% of which are single-phase ground faults, and phase-to-phase faults are mostly formed by single-phase ground faults that have not been detected and processed in time. When a high-resistance grounding fault occurs in the distribution network (tree barriers, incomplete breakdown of lightning arresters, etc.), the transition resistance is often as high as several thousand ohms, the fault characteristic value is very weak, and the neutral point displacement voltage is far less than the 15% phase voltage of th...

AI Technical Summary

Problems solved by technology

Among them, the direct method and the indirect method need to change the primary parameters of the system or the topology of the system, the operation is complicated and there is a risk of electric shock, and it is not suitable for real-time measurement of system parameters.

Images