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

Abstract

The invention discloses a method for processing an interphase short circuit of three-phase power supply system. A plurality of controlled switches are distributed on a three-phase power supply system, when a two-phase or three-phase interphase short circuit occurs in a line, one fault phase of the line is maintained to be conducted, other fault phases are tripped off, another faulty phase conducted with the fault phase is cyclically connected to and disconnected from a bus, the number of current pulses triggered and cut off by a controlled switch at the downstream of the power supply is set to be less than the number of current pulses triggered and cut off by the controlled switch at the upstream of the power supply, and the interphase short circuit fault can be eliminated by cutting off the line after a certain controlled switch reaches a triggering condition. According to the method, the interphase short-circuit fault point interval can be quickly positioned, the fault can be automatically, quickly and accurately removed, the processing quality of the interphase 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 after a phase-to-phase short circuit fault occurs in a three-phase power supply system. Background technique [0002] At present, when a phase-to-phase short circuit occurs in a certain line of a three-phase power supply system, the usual method is: 1. Adopt the mode of reclosing: first cut off the first circuit breaker on the line and then close the first circuit breaker, if It is an instantaneous phase-to-phase short circuit, and it will be eliminated after closing the first circuit breaker, and 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 according to...

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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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