Open-phase protection logic implementation method of three-phase linkage type circuit breaker

Abstract

The invention relates to the technical field of relay protection, in particular to an open-phase protection logic implementation method of a three-phase linkage type circuit breaker. The method comprises the following steps of S1, judging whether to start the open-phase protection and an energy supply mode of a generator set via a protection device and according to the change of a GCB position contact; S2, during the grid connection or disconnection of the generator set, adopting a grid connection criterion and a disconnection criterion to judge whether a protection action condition is met or not; and S3, when any criterion meets the protection action condition, stopping the protection action or alarming. According to the invention, a multi-mode and multi-criterion open-phase protection logic is designed, the actual situation of a power plant site can be met, and the problem that the existing GCB open-phase protection purely takes the negative-sequence current or zero-sequence voltage as a single criterion, is solved.

Description

technical field [0001] The invention relates to the technical field of relay protection, in particular to a non-full-phase protection logic implementation method for a three-phase linkage circuit breaker. Background technique [0002] At present, the three-phase linkage generator outlet circuit breaker (hereinafter referred to as GCB) has been widely used in hydroelectric power plants. However, due to reasons such as mechanical structure and frequent operation, the GCB may have inconsistent three-phase states during the opening and closing process. At this time, zero-sequence and negative-sequence voltage components will be generated on both sides of the GCB, and negative-sequence current will flow through the stator winding at the same time, thereby generating a negative-sequence magnetic field. Then the rotor is burned, and the vibration of the unit is increased due to the existence of the negative sequence magnetic field, which may cause metal fatigue and mechanical dama...

AI Technical Summary

Problems solved by technology

At this time, zero-sequence and negative-sequence voltage components will be generated on both sides of the GCB, and negative-sequence current will flow through the stator winding at the same time, thereby generating a negative-sequence magnetic field. Then the rotor is burned, and the vibration of the unit increases due to the existence of the negative sequence magnetic field, which may cause metal fatigue and mechanical damage

Due to the different loads of the unit when the GCB is opened and closed, the electrical quantities such as zero-sequence voltage and negative-sequence current are also different when a non-full-phase fault occurs. The existing GCB non-full-phase protection only uses negative-sequence current or zero-sequence voltage etc. as the criterion may cause the protection to refuse to operate when the GCB non-full-phase fault occurs under the condition of small load. Therefore, according to the actual situation of the power plant site, it is necessary to design a multi-criteria and multi-mode GCB non-full-phase protection logic

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