Discrimination Method of Interturn Short-Circuit and Resistive Unbalance Faults for Synchronous Condenser

In this paper, a discrimination method is proposed for the interturn short-circuit and resistive unbalance faults of the synchronous condenser. The mathematical models of the synchronous condenser are established under these two faults. Especially, the zero-sequence voltage components (ZSVC) under two faults are analyzed. Due to the direct connection between the synchronous condenser and the power grid, the fundamental component of ZSVC under the interturn short-circuit fault is not affected by the stator currents, while the resistive unbalance fault is just the opposite. Hence, the amplitude of fundamental component in ZSVC is used to detect the fault occurrence. Then, the change of the fundamental component in ZSVC is observed by changing the excitation current to discriminate the fault type. The effectiveness of the proposed method is verified by the simulation and experimental results.