Method for processing interphase short circuit of three-phase non-effective grounding power supply system

Abstract

The invention discloses a method for processing interphase short circuit of a three-phase non-effective grounding power supply system. The method comprises the following steps: when two-phase or three-phase interphase short circuit occurs in a line, maintaining one fault phase of the line to be conducted and tripping off other fault phases, and artificially grounding the other fault phase conducted with the fault phase or directly utilizing the existing grounding point; enabling a live-line phase or a neutral point of the three-phase non-effectively grounded power supply system except the fault phase to be circularly connected and disconnected with the ground, so that the live-line phase or the neutral point and the fault phase form a closed loop and generate a current pulse, and detecting the current pulse by a controlled switch; when a certain controlled switch reaches a trigger condition and cuts off a line, eliminating a fault. According to the method, the inter-phase short-circuit fault point interval can be quickly positioned, the fault can be automatically, quickly and accurately removed, the processing quality of the inter-phase short-circuit fault can be well improved, and the power supply safety is improved.

Description

technical field [0001] The invention relates to the field of fault processing of power supply systems, in particular to a processing method for phase-to-phase short-circuit faults in a three-phase non-effectively grounded power supply system. Background technique [0002] At present, when a phase-to-phase short circuit occurs in a line of a three-phase non-effectively grounded power supply system, the usual method is: 1. Use the reclosing method: first cut off the first circuit breaker on the line and then close the first breaker If it is an instantaneous phase-to-phase short circuit and it is eliminated after closing the first circuit breaker, the normal power supply will continue. If the phase-to-phase short-circuit fault still exists after closing the first circuit breaker, cut off the first circuit breaker and wait for maintenance. 2. Adopt the time-level difference coordination method: that is, the same line circuit breaker sets different over-current tripping times ac...

AI Technical Summary

Problems solved by technology

2. Adopt the time-level difference coordination method: that is, the same line circuit breaker sets different over-current tripping times according to the distance from the power supply. The closer the distance to the power supply, the longer the tripping time. Generally, the setting level difference is 100ms. This time is determined by the mechanical switch. The action duration is determined by the time spent on the algorithm. This method can isolate the fault area. However, for faults where the fault point is close to the power supply, the power supply system can withstand short-circuit current for a long time and have a large impact on the power grid.

However, during this operation, the uncut circuit breaker and the power supply system are continuously subjected to a large short-circuit current impact. If the time is too long or the number of times is too high, the circuit will be damaged.

If the duration of the phase-to-phase short circuit cannot exceed 300 milliseconds, and the circuit breaker trip time is 100 milliseconds, then generally there should not be more than three circuit breakers on the line, otherwise the above method may cause the line to exceed 300 milliseconds.

It can be seen that the existing interphase short circuit processing methods all have the disadvantages of taking a long time to deal with the fault and not being able to automatically eliminate the fault

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