Identification of the Distribution Network´s Grounding Status based on Frequency Track Method

In the resonant-grounded distribution network, series resonance between the Peterson coil and the network zero-sequence capacitance after an arc incident presents great danger to the safe operation of the network. The key to solve this problem is to identify the exact arc extinguishing time. Based on the principles of transformer-based arc suppression coil (TASC), this paper introduces an arc extinguishing timing identification method, namely, frequency track method (FTM). The relationships between the thyristor´s triggering angle of the TASC and the frequency of the neutral point voltage is utilized in this proposed method. Laboratory and field tests have been carried out to verify the proposed method.