Analysis of rotor winding interturn short circuits affected by the initial dynamic eccentricity in large synchronous condensers

To investigate the effect of initial dynamic eccentricity on the rotor winding turn-to-turn short circuit (RWISC) in a large synchronous condenser, this paper uses the study object of a 300 MVar dual water intercooler condenser. Firstly, the air gap flux density characteristics, unbalanced magnetic pull (UMP) and stator circulating current of the condenser under single and compound faults are derived theoretically. Then, a phase-modulated field-circuit coupling model is constructed using Anosoft software. It is used to simulate and analyse the condenser. Finally, the operation of the condenser was simulated with the SDF-9 experimental setup, and the correctness of the theoretical derivation and simulation analysis was verified. The results show that the initial dynamic eccentricity of the condenser has a cutting effect on the fault characteristics generated by the RWISC. The 2nd harmonic of air gap flux density and stator circulating current and the fundamental wave of UMP decrease and increase with eccentricity. This study can provide theoretical guidance to eliminate disturbing factors to improve the accuracy of RWISC diagnosis in large synchronous condensers.