A zero-sequence blocking digital current protection method

Abstract

The invention discloses a zero-sequence blocking digital current protection method, which comprises the following steps: the implementation of digital current protection is divided into two parts: phase-separated digital current protection and zero-sequence digital current protection, and phase-separated digital current protection and zero-sequence digital current protection are simultaneously configured Digital current protection; when the short-circuit fault current does not contain zero-sequence current, the zero-sequence digital current protection does not operate, and the fault is cut off by the phase-separated digital current protection; when the short-circuit fault current contains zero-sequence current, the zero-sequence digital current protection operates And the phase-separated digital current protection is blocked, and the ground fault is cut off by the zero-sequence digital current protection action. The invention solves the problem that the phase-separation digital current protection is easy to malfunction when a high-resistance grounding fault occurs through the cooperation of phase-separation and zero-sequence digital current protection, and has a wider application range and great practical value.

Description

technical field [0001] The present invention relates to a zero-sequence blocking type digital current protection method suitable for AC ring network power supply systems of subways, urban light rails and trams, and power supply systems in other fields with similar network structures, especially a zero-sequence blocking method Type digital current protection method. Background technique [0002] For the urban rail transit power supply system that adopts the ring-series power supply mode, the digital current protection has strong selectivity, short action time, and can be applied to a variety of operation modes, so it is more and more widely used in the medium-voltage power supply system of the subway. [0003] However, with the deepening of the application, the digital current protection has also shown some shortcomings in the application process, which needs to be improved. The specific performance is that when the phase-separated digital current setting value and the fault...

AI Technical Summary

Problems solved by technology

[0007] However, the actual high-resistance grounding fault is in the 103 protection area, so the 102 circuit breaker is a malfunction, which leads to the expansion of the blackout range and poses a serious threat to the reliability of the power supply system.

[0008] For the above fault types, there is no mature solution in the public information

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