Single-phase earth fault recognizing method for power distribution network

Abstract

The invention discloses a single-phase earth fault recognizing method for a power distribution network, and relates to the technical field of power distribution networks. The recognizing cost of a single-phase earth fault can be lowered. According to the method, the maximum negative-sequence current change absolute value and the minimum negative-sequence current difference value are calculated first according to the negative-sequence current value of each outlet line of a power distribution network busbar at the present moment and the negative-sequence current value of the outlet line at the previous moment, then, the fault index is further figured out by combining the zero-sequence current value of the power distribution network busbar at the present moment and the zero-sequence current value of the power distribution network busbar at the previous moment, and afterwards, whether the single-phase earth fault happens to the power distribution network or not is judged according to the fault index. The single-phase earth fault recognizing method for the power distribution network is suitable for recognizing the single-phase earth fault in the power distribution network.

Description

technical field [0001] The invention relates to distribution network technology, in particular to a technology for identifying a single-phase ground fault in a distribution network. Background technique [0002] Most distribution networks operate in non-effective grounding mode. When a single-phase ground fault occurs in the distribution network, since the short-circuit current is grounded through the arc suppression coil, the grounding current is very small, and the distribution network is three-phase in normal operation. Phase asymmetric operation, there is negative sequence current, so the single-phase ground fault of the distribution network is often difficult to identify, and it is often necessary to configure special detection equipment to assist identification, thereby increasing the cost of the distribution network. Contents of the invention [0003] In view of the defects existing in the above-mentioned prior art, the technical problem to be solved by the present ...

AI Technical Summary

Problems solved by technology

[0002] Most distribution networks operate in non-effective grounding mode. When a single-phase ground fault occurs in the distribution network, since the short-circuit current is grounded through the arc suppression coil, the grounding current is very small, and the distribution network is three-phase in normal operation. Phase asymmetric operation, there is negative sequence current, so the single-phase ground fault of the distribution network is often difficult to identify, and it is often necessary to configure special detection equipment to assist identification, thus increasing the cost of the distribution network