Differential power distribution network single-phase ground fault property and fault recovery judgment method

Abstract

The invention provides a differential power distribution network single-phase ground fault property and fault recovery judgment method. In a low-resistance ground fault area and an intermediate-resistance ground fault area, the property of a single-phase ground fault is judged according to the neutral point displacement voltage U<N> of a power distribution network; and in a high-resistance groundfault area, the property of the single-phase ground fault is judged according to the zero-sequence current I<m0> of a fault feeder. When the single-phase ground fault is judged to be a permanent ground fault in the low-resistance ground fault area and the intermediate-resistance ground fault area, whether or not a fault line is cut off is judged according to the neutral point displacement voltageU<N> of the power distribution network, and a ground fault processing device resets. When the single-phase ground fault is judged to be a permanent ground fault in the high-resistance ground fault area, whether or not the single-phase ground fault line is cut off is judged according to the zero-sequence current I<m0> of the fault feeder, and the device resets.

Description

technical field [0001] The invention belongs to the field of rapid diagnosis method and processing of single-phase grounding fault properties of distribution network, and is mainly used for judgment and processing of instantaneous grounding fault and permanent grounding fault of distribution network. Background technique [0002] There are two types of ground faults in the distribution network: one is instantaneous faults. In this case, the insulation at the fault point is not destroyed, but a transient ground fault occurs. Discharge to the ground under the condition of overvoltage or pollution migration, etc., once the discharge is closed, the insulation of the fault point will be restored, and the power grid will resume normal operation; the other type is a permanent fault, and the fault cannot be recovered by itself. The insulation of the fault point is permanently damaged, that is, the discharge junction, the insulation at the fault point will not be restored, and the po...

AI Technical Summary

Problems solved by technology

[0004] However, it is not acceptable to use the distribution network neutral point displacement voltage method for single-phase high-resistance grounding faults, because when a single-phase high-resistance grounding fault occurs in the distribution network, the neutral point displacement voltage U of the distribution network N When a single-phase high-resistance grounding fault occurs in a certain phase in an asymmetrical power grid, the neutral point displacement voltage U of the distribution network N Not only will it not increase, but it will also decrease. In this way, it is impossible to judge whether the ground fault is restored by using the neutral point displacement voltage method of the distribution network, and it is impossible to judge whether the ground fault is an instantaneous ground fault or a permanent ground fault, and it is also impossible to judge the ground fault Whether the line is cut off from the grid, and the ground fault processing device resets