Study Of Circulating Current In Stator Bars Of Hydro-generator

The circulating current in the stator bars of Hydro-generator causes high temperature in strands, serious aging of insulation layer and limit of the output of the motor. Related research has attracted great attention. This paper focuses on expanding the scope of multi-section method coupled field-circuit in calculating circulating current. It is used in 4 kinds of transpositons,360° transposition,360° transposition with a void, less than 360° transposition and more than 360° transposition. The algorithms of the leakage reactance and Leakage inductance potential are derived in detail in 4 kinds of transpositions by the analytical method and the multi-section method coupled field-circuit. The calculation of circulating current of a stator coil strands is analyzed by three methods, strands loop method, leakage fields EMF method and node voltage method. The paper focuses on the circulating current loss in the strands of stator bar of Hydro-generator.Combined with the engineering example, this paper emphasizes the analytical method and the multi-section method coupled field-circuit for solving the circulating current loss and optimal transposition of 4 kinds of transpositions. The results show that magnetic field of stator is similar and that the electrical parameters and the circulating current loss are close by the two methods. To sum up, the process of the multi-section method coupled field-circuit is simpler and the accuracy is better. And there is no need to derive the calculation formula of the electrical parameters of strands for new transpositions by the multi-section method coupled field-circuit.