Evaluation Method of Arcing Contacts Erosion State of SF6 Circuit Breakers

Due to arc erosion, the arcing contacts of highvoltage SF6 circuit breakers gradually deteriorate throughout the working life, and in severe cases will lead to failure to break and cause significant property damage. Therefore, it is important to timely and accurately evaluate the state of contact erosion. Extracting characteristic parameters based on the dynamic resistance curve of the SF6 circuit breakers are an effective technique for evaluating the erosion state of arcing contacts. However, the traditional characteristic parameters have a small application range and the evaluation effect is poor. In this paper, the characteristic parameter FN is extracted from the dynamic resistance curve by the frechet distance method, which is used to evaluate the erosion state of arcing contacts and classify it. The results show that the characteristic parameter FN has a high fault tolerance rate, a wide range of application, and an excellent evaluation effect. FN can be combined with traditional characteristic parameters to jointly evaluate the erosion state of arcing contacts, making the dynamic resistance method more complete.