Fault Analysis and Treatment of Insufficient Arc Extinguishing of SF6 Circuit Breaker

In this paper, a 35 kV circuit breaker arc in a 220 kV substation is not extinguished, which leads to the damage of the low voltage side winding of the main transformer. The cause of the fault is analyzed and the relevant treatment measures are put forward. Firstly, the wave recording message and the fault site are checked. Combined with the previous operation data, the equipment ontology and the modeling simulation analysis, the causes of the fault are analyzed from the waveform segmentation analysis results to the equipment inspection and the corresponding principle analysis. Then the cause of the fault is that the bolt and adsorber of the B-phase arc extinguishing chamber of the circuit breaker are not fixed firmly, which leads to the circuit breaker not completing the opening and arc extinguishing. The continuous arc causes the fault grounding of the B-phase arc extinguishing chamber, and then develops into a three-phase grounding fault. The short-circuit current causes the circuit breaker and the switch cabinet to burst. Finally, the measures to prevent such faults and the next step plan are summarized to ensure the safe and stable operation of the power grid.