Circuit breaker non full phase judging method based on two-side voltage fundamental wave amplitude ratio

Abstract

The invention discloses a circuit breaker non full phase judging method based on a two-side voltage fundamental wave amplitude ratio. A protection device is used for measuring three-phase voltage and open delta voltage at the left side and the right side of the circuit breaker; fundamental wave amplitudes of the three-phase voltage and the open delta voltage at the left side and the right side of the circuit breaker and the ratio of the fundamental wave amplitudes of the open delta voltage at the left side and the right side are calculated respectively; when the fundamental wave amplitudes of the three-phase voltage at the left side and the right side are both larger than eta% of rated voltage, when the fundamental wave amplitudes of the open delta voltage at the left side and the right side are both larger than a fundamental wave amplitude threshold, and when the fundamental wave amplitude ratio of the open delta voltage at the left side and the right side is larger than a ratio fixed value threshold, circuit breaker non full phase is judged, and alarming or tripping is carried out after a short time delay t. The method does not rely on the magnitude of negative-sequence current and solves the problem that when non full phase happens to the circuit breaker in the case of light load and the previous negative sequence current criterion can not be recognized; and in addition, as the method does not need to judge a three-phase inconsistent contact of the circuit breaker, the non-full phase judging problem of a three-phase linked circuit breaker can also be solved.

Description

technical field [0001] The invention belongs to the field of relay protection of electric power systems, and in particular relates to a method for judging incomplete phase of a circuit breaker based on the ratio of fundamental voltage amplitudes on both sides. Background technique [0002] At present, the non-full-phase protection of circuit breakers widely used in the field is generally composed of three-phase inconsistent contacts and negative sequence current criteria. Very small, it is difficult to exceed the negative sequence current setting value, and it is impossible to judge that the circuit breaker is not in full phase. Generator machine-side circuit breakers are generally three-phase linkage, do not provide three-phase inconsistent contacts, and cannot adopt traditional non-full-phase protection. There have been many accidents in the field where one-phase tie rod of the machine-side circuit breaker broke and caused non-full-phase accidents. Full-phase protection c...

AI Technical Summary

Problems solved by technology

[0003] The main purpose of the present invention is to provide a circuit breaker non-full-phase judgment method based on the ratio of the voltage fundamental wave amplitude on both sides. The problem that the current criterion cannot be identified. In addition, since this method does not need to judge the three-phase inconsistent contacts of the circuit breaker, it also solves the problem of non-full phase discrimination of the three-phase linkage circuit breaker

Images