During the actual operation of the hydro-generator, there is often a dynamic inter-turn short-circuit fault of the rotor winding. However, it is difficult to locate the fault since it will disappear after the generator is shutdown. Hence, in order to quickly eliminate the dynamic inter-turn short-circuit fault of hydro generator, this paper presents a theoretically analysis of the relationship between the position of the fault magnetic pole and the harmonic phase of stator unbalanced current. Firstly, combined with the characteristic of polarity between two adjacent poles, the spatial phase difference of two adjacent magnetic poles is analyzed to obtain the relationship between the harmonic expression of unbalanced stator current and the position of the fault magnetic pole. Secondly, through the specific analysis of a synchronous generator with six poles, the changing law of the fractional harmonic phase of the stator unbalanced current in general synchronous generator is obtained. Then an on-line location method of fault magnetic poles of the hydro-generator based on harmonic phase of stator unbalanced current is proposed. Simulation and field experiment are carried out finally, which both show that the method proposed in this paper can effectively realize the real-time monitoring and on-line location of fault magnetic poles of the hydro-generator.

hydro-generator;rotor winding inter-turn short-circuit fault;unbalanced stator current;power system harmonics;online locating