Power distribution network grounding fault recognition method, device and equipment

Abstract

The invention discloses a power distribution network grounding fault recognition method, a device and equipment. The method comprises the following steps: firstly, injecting same-amplitude variable-frequency small-current signals from a neutral point of a power distribution network; measuring a feedback voltage signal by a voltage transformer, and calculating the ground conductance and the groundcapacitance of the power distribution network; calculating the incremental damping rate under each frequency by using the ground conductance and the ground capacitance, calculating and superposing theincremental damping rate generated by the fault transition resistance to perform the fault according to the preset criterion so as to realize the effective amplification of the fault characteristic quantity and greatly reduce the influence of the interference, thereby effectively identifying the high-resistance grounding fault. According to the method, the problem that the high-resistance grounding fault of the resonant grounding power distribution network is difficult to identify is solved, the grounding fault characteristics can be highlighted, the method has high anti-noise capability, andthe recognition capability of the high-resistance grounding fault is greatly improved.

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...

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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.

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