System and method for starting failure protection of generator injection ground protection

Abstract

The invention discloses a system and method for generator injection-type grounding protection starting failure protection. The system includes a main transformer, a busbar, an overhead line, etc.; Connection, the high voltage side of the main transformer is connected to one end of the grid-connected circuit breaker through the first set of overhead lines, and the other end of the grid-connected circuit breaker is connected to the busbar through the second set of overhead lines. The method includes the steps of: starting the generator injection type grounding protection action and starting the failure protection at the same time; judging that the three-phase current value collected by the generator terminal current transformer is greater than or equal to the current threshold value, and if the judging result is "yes", delaying for 150ms Then proceed to this step. If the judgment result is "No", it proves that the grid-connected circuit breaker has tripped, and then enter the next step; block the action of the injection-type grounding protection of the generator. The invention solves the problem that the injection type grounding protection of the generator cannot be started and fails to protect, and has the advantages of reasonable outlet mode, accurate discrimination and strong adaptability.

Description

technical field [0001] The invention belongs to the technical field of relay protection, and in particular relates to a system and method for generator injection-type grounding protection starting failure protection. Background technique [0002] The generator injection ground fault protection is used to respond to the ground fault of the generator stator (or rotor). The principle of generator injection grounding protection is that the auxiliary power supply device provides external low-frequency power, injects low-frequency voltage and current signals into the stator (or rotor) winding of the generator, and then detects the injected low-frequency voltage and current signals by the protection device. When a ground fault occurs in the stator (or rotor) winding of the generator, the injected low-frequency voltage and current signals also change accordingly. The protection device calculates the collected low-frequency voltage and current signals through the admittance method. I...

AI Technical Summary

Problems solved by technology

[0006] The present invention aims at the deficiency that the circuit breaker failure protection cannot be started after the injection grounding protection action of the existing generator, and provides a system and method for starting failure protection of the generator injection grounding protection, which is suitable for the injection grounding protection of the generator, Improves the defect that the failure protection of the circuit breaker cannot be started, and has the characteristics of no need to add additional equipment, and the export method is reasonable.

Images