Inverse time lag current protection method

Abstract

The invention relates to an inverse time lag current protection method. The method comprises steps that (1), the motion delay time of a sending and a receiving end of a high resistance distance relay is respectively calculated when protection mounting portions A, B and C are in three-phase faults; (2), the zero sequence current inverse time lag protection motion time of the sending end and the receiving end of the three-phase high resistance distance relay is respectively calculated; and (3), time relationships between high resistance distance protection and zero sequence current inverse time lag motion protection of the sending end and the receiving end of the three-phase high resistance distance relay are determined. The method is for zero sequence current inverse time lag protection and distance protection matching, a general fault scope can be determined through distance protection, a zero sequence current inverse time lag protection motion speed is accelerated, the inverse time lag protection motion time can be effectively shortened, skip-level motion can be prevented, and motion performance of zero sequence current inverse time lag protection under high resistance fault conditions is improved.

Description

technical field [0001] The invention relates to an inverse-time-limit current protection method, in particular to a method for coordinating inverse-time-limit current protection and distance protection. Background technique [0002] The action time of the inverse time overcurrent protection is related to the fault current and changes with the magnitude of the short-circuit current. The short-circuit current is large, the action time is fast, and the short-circuit current is small, the action time is slow, showing an inverse time-limit characteristic. The action time of relay protection is related to the magnitude of the short-circuit current, which is inversely proportional. [0003] Inverse time overcurrent protection is widely used in the protection of generators, transformers, motors and distribution networks. In order to meet the requirements of different equipment for inverse time-lag characteristic curves, the microcomputer protection device needs to provide a variety...

AI Technical Summary

Problems solved by technology

[0005] The action performance of the traditional zero-sequence current inverse time protection is limited by the wiring mode of the line. In the case of boosting current in the lower line, the boosting current will cause the inverse time limit leapfrog action; at the same time, when the fault current is small, The action time of inverse time limit protection is longer

Therefore, the scope of application of inverse time protection is easily limited

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