Modeling and Detection of Turn-to-Turn Faults in Shunt Reactors

In this paper, the analysis and simulation of shunt reactor turn-to-turn faults, as well as the algorithms for their detection, are presented. A simple equivalent circuit of a shunt reactor applicable for a small number of short-circuited turns was developed and applied to simulate such faults. It is shown why the commonly applied differential relays are not able to detect turn-to-turn faults. Then three new algorithms are introduced, and their performance is analyzed for simulated internal faults. The proposed methods are based on zero-sequence reactance, negative-sequence reactance, and phase impedance. The sensitivity and security of the presented methods are discussed. The proposed algorithms’ performance has been tested with the signals generated with the use of the MATLAB/Simulink program. The results confirm that the proposed algorithm can effectively improve the detection of turn-to-turn faults. The paper ends with recommendations for the setting of the proposed protection schemes.