Single-phase earth fault recognizing method for power distribution network

A single-phase-to-ground fault and identification method technology, applied in the field of distribution network, can solve the problems of increased distribution network cost, small grounding current, and difficulty in identifying single-phase-to-ground faults in distribution network, so as to reduce identification costs and be easy to implement. , the effect of high recognition accuracy

Inactive Publication Date: 2014-09-17
SHANGHAI SUNRISE POWER TECH +1
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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

Method used

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Embodiment Construction

[0026] The technical solution of the present invention is further described in detail below in conjunction with specific examples, but the present examples are not intended to limit the present invention, and all similar structures and similar changes of the present invention should be included in the protection scope of the present invention.

[0027] A method for identifying a single-phase-to-ground fault in a distribution network provided by an embodiment of the present invention is characterized in that the specific steps are as follows:

[0028] 1) Set the current time as T, obtain the zero-sequence current value of the distribution network bus at time T and T-Δt time, and obtain the negative sequence current value of each outgoing line of the distribution network bus at time T and T-Δt time;

[0029] Among them, Δt is a preset time constant, and the typical value of Δt is 1 minute;

[0030] 2) Calculate the absolute value of the negative sequence current change of each o...

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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 ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/08
Inventor 李昌夏湘洪
Owner SHANGHAI SUNRISE POWER TECH
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