Method for judging ground fault of distribution network line of non-grounding system

Abstract

The invention discloses a method for judging a ground fault of a distribution network line of a non-grounding system. The method comprises the following steps of acquiring three-phase current at each switch position on the distribution network line, when the power distribution switch monitoring terminal detects that zero-sequence current jump exceeds a set threshold value, extracting and calculating the three-phase current variable quantity, wherein the zero-sequence current is the three-phase current when a grounding fault occurs, and determining a fault position according to the three-phase current variation relationship, and forming alarm information. Compared with the prior art, the ground fault is judged through collection or synthesis of zero sequence current, the collection result and the judgment result are accessed to the power distribution switch monitoring terminal, the position of the ground fault is accurately judged through an algorithm, correct judgment of the ground fault can be ensured, and a decision is made for dispatching monitoring, rapid fault isolation and power supply recovery.

Description

technical field [0001] The invention relates to a method for judging a grounding fault of a distribution network line of a non-grounding system, and belongs to the technical field of judgment of a grounding fault of a distribution network line. Background technique [0002] The existing distribution network line is a non-grounded system. Since the zero-sequence current is small and unstable when a ground fault occurs, it is difficult to sketch the setting value of the automatic switch, and the correct action cannot be identified, resulting in the protection action of the substation's small current grounding line selection when the ground fault occurs. Isolation of faults, wide range of power outages, and difficulty in fault finding. Contents of the invention [0003] Based on the above, the present invention provides a method for judging the grounding fault of the distribution network line of the non-grounding system, so as to solve the difficulty in sketching the automati...

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Problems solved by technology

[0003] Based on the above, the present invention provides a method for judging the grounding fault of the distribution network line of the non-grounding system to solve the difficulty in sketching the automatic switch setting value in the prior art, unable to identify the correct action, and relying on the small current grounding line selection protection of the substation when the grounding fault occurs Action to isolate faults, wide range of power outages, and difficult fault finding

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