Research on generator stator ground fault injection online location method based on multi-mode grounding

Aiming at the problem of online fault location of large generator stator and the lack of research status of on-line fault location method under multi-mode grounding condition of generator stator, an injection type on-line fault location method under multi-mode grounding condition of large generator stator is proposed. By injecting non-power frequency signal into the secondary side of grounding transformer under multi-mode grounding mode, the voltage and current values of power frequency and non-power frequency returned by the system are fused, and the value of system grounding fault transition resistance is calculated, and the expression of sub grounding transition resistance and fault location is determined. By analyzing the analytic relationship between the system neutral voltage and the fault phase voltage, the stator ground fault location of large generator is solved. The PSCAD/EMTDC simulation model is built to verify that this method can effectively adapt to the demand of real-time online fault location of stator multi-mode grounding mode, with low positioning error, reducing fault finding time and economic loss caused by shutdown.