Zero-sequence blocking digital current protection method

Abstract

The invention discloses a zero-sequence blocking digital current protection method which comprises the following steps: when in implementation, digital current protection is divided into two parts, namely phase-segregated digital current protection and zero-sequence digital current protection, and meanwhile, the phase-segregated digital current protection and the zero-sequence digital current protection are configured at the same time; when a short-circuit fault current does not contain a zero-sequence current, the zero-sequence digital current protection does not act, and a fault is cut off under the action of the phase-segregated digital current protection; when the short-circuit fault current contains the zero-sequence current, the zero-sequence digital current protection acts and blocks the phase-segregated digital current protection, and a ground fault is cut off under the action of the zero-sequence digital current protection. Through matching of the phase-segregated digital current protection and the zero-sequence digital current protection, the problem that the phase-segregated digital current protection is liable to act by mistake when the high-resistance ground fault occurs can be solved, the protection application range is wider, and the practical value is greater.

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 type of upload failure, there is no mature solution in the public information

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