Research On The Protection Of 1000MW Generator Rotor Grounding

Generator rotor winding ground fault is a more common generator fault. This paper summarizes the synchronous generator the main types of electrical fault. Between the rotor windings of the fault causes and the current detection methods at home and abroad to carry out the main understanding of the specific analysis. And in this paper we conclude the Ping-pong type protection and injection rotor ground protection. Current ping-pong type of field winding ground protections cannot detect grounding fault of field winding while generator is in free-running operation or shut down. To remedy this defect, we propose an improved scheme for ping-pong type field winding ground protection, that is ,a DC voltage is injected into field winding and switching-over circuit is connected in parallel with the injected voltage. The principle of this improving scheme and the criterion for protection action are given; several problems such as the calculation method of grounding resistance, the selection of parameters in switching-over circuit and that of switching-over period are analyzed. Simulation results show that the accuracy and sensitivity of the improved scheme can meet the requirement of practical operation. According to the real situation of 1000 Mw generator, this paper analyses the problems which is brought by 1000MW generator especially and summarizes the ways to solute these problems. At last, the Simulation results show that the accuracy and sensitivity of the improved scheme can meet the requirement of practical operation.