A Rotor Winding Internal Short-Circuit Fault Protection Method for Variable-Speed Pumped Storage Units

In electrical machinery, the rotor windings’ internal short-circuit faults are addressed by instantaneous over-current protection of power electronic excitation device, which has low sensitivity and difficulty meeting safety requirements. this paper, a fault method is proposed based on harmonic characteristics circulating current between stator branches. The magnetomotive force distribution coils in windings theoretically deduced, characteristic frequencies branches analyzed. On basis, criterion constructed using component current. Then, an analytic model variable-speed pumped storage unit established multi-loop method, finite element used to verify correctness modeling method. An actual large taken as example, possible under different slip ratios simulated. simulation results, branch circulation obvious frequency components, consistent with theoretical analysis. It verifies effectiveness Finally, it analyzed verified that strong maloperation prevention ability other kinds faults.