Analysis of the misoperation process for inter-turn protection of high voltage shunt reactor connected with Submarine Cable

In view of the misoperation of the inter-turn protection of high voltage shunt reactor(HVSR) connected with submarine cable in offshore wind power project during the conventional opening and closing operation, a comparative analysis of the inter-turn protection principles of different manufacturers and analytical analysis of the misoperation process of the operation sceneis are carried out. Based on the analytical analysis, two scenarios of misoperation are summarized, namely, the zero-sequence source generated by the saturation of the iron core during closing is judged to be mistaken as an internal fault, and the measurement impedance decreases due to the increase of the current amplitude during the resonance period. The simulation reproduces the recorded waveform of the scene, and the correctness of the analytical analysis is verified. Finally, some countermeasures and suggestions are given, such as increasing appropriate harmonic restrain criteria, increasing resonant frequency identification criteria, and the break near reactor should close first and then open last during operation.