Fault diagnosis method based on multi-source information fusion for weak interturn short circuit in synchronous condensers

The interturn short circuit fault in rotor windings is a common fault in a synchronous condenser. Aiming at the early faults that are difficult to detect, the theory of multi-source information fusion is applied herein for the identification of short circuit faults in the rotor windings of a synchronous condenser. Firstly, a field-circuit-network coupling model of a synchronous condenser for high-voltage direct current (HVDC) transmission was constructed using SIMULINK/ANSYS. The air gap magnetic flux density of the interturn short circuit regulator with a rotor winding was obtained, via co-simulation, before and after the commutation failure in the HVDC inverter. Further, three-dimensional models of the stator and rotor of the synchronous condenser were established using ANSYS/Workbench; the stator and rotor vibration responses of the synchronous condenser were monitored before and after the system commutation failure. Secondly, three types of evidence bodies were obtained based on the Dempster-Shafer evidence theory. The results show that the confidence level of the evidence body of each faulted component of the synchronous condenser increases, and the accuracy of fault recognition also increases upon system commutation failure. Finally, a three-pair-pole synchronous motor (MJF-30-6) was used to simulate the rated and overexcited operations of the synchronous condenser for experimental verification of the feasibility of the proposed method. This method provides a reference for the identification of weak interturn short circuit faults in synchronous condensers.