Abstract: Using the functional relationship between the internal electromotive force E of generator and the excitation current If of the rotor, the criterions of the generator rotor turntoturn short circuit and the rotor grounding fault were analyzed and summarized. The data of the generator in 600MW unit of Sichuan Guang'an Power Generation Company Limited before and after the rotor turntoturn short circuit and rotor grounding fault were analyzed, and the rotor was pulled out and inspected. The data analysis and practical inspection prove the correctness of the criterions. The measures for preventing the rotor grounding fault were put forward, which are useful for enhancing the fault analysis ability of the operators.

Key words: generator, rotor, turn-to-turn short circuit, grounding fault, analysis, preventive measures