Distribution network ground fault arc extinction and protection method

Abstract

The invention discloses a distribution network ground fault arc extinction and protection method, which comprises the following steps of: measuring a three-phase voltage and a zero sequence voltage of a distribution network, and detecting a ground fault and a fault phase; when the ground fault happens, injecting a current into the distribution network and forcibly zeroing the voltage of the faultphase and the current of the ground fault; delaying a period of time and reducing the injected current; if the zero sequence voltage is reduced proportionally, indicating that the fault point is subjected to arc extinction, determining that the fault is an instant fault, reducing the injected current to zero and recovering the normal running of the distribution network; otherwise, determining that the fault is a permanent fault, changing the injected current, detecting and isolating a fault feed line according to the variation of a zero sequence current, and recovering the normal running of the distribution network. By the method, the voltage of the fault phase is used as a control target, so total arc extinction of the instant fault and quick isolation of the permanent fault can be realized by injecting the current and forcibly zeroing the voltage of the fault phase; and the technical difficulties in poor arc extinction effect of the current arc extinction method and low reliability of the conventional protection method are overcome.

Description

technical field [0001] The invention relates to a grounding fault arc suppression and protection method of a distribution network. Background technique [0002] The distribution network goes deep into the user terminals, and the operating environment is changeable, prone to random failures. About 70% of faults are transient ground faults. There are capacitance and leakage resistance to the ground in the distribution network, and the ground fault current is capacitive current and leakage current. In order to limit the ground fault current, the distribution network in my country generally adopts ungrounded neutral point, grounded through arc suppression coil, grounded through resistance, etc. The neutral point is not effectively grounded. With the development of urban and rural power grids, the capacitive current increases, and the arc suppression ability of instantaneous ground faults is poor. The "continuous operation" accident caused large-scale power outages, endangered ...

AI Technical Summary

Problems solved by technology

[0007] The invention provides a novel arc suppression and protection method for grounding faults in distribution networks, which realizes 100% arc suppression for instantaneous faults and fast tripping isolation for permanent faults, thereby reducing the probability of phase-to-phase faults and shortening the operating time of distribution networks with faults , effectively avoid the occurrence of "fire joint operation" accidents, and solve the technical problems of poor arc suppression effect of distribution network faults and low reliability of existing protection methods

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