Circuit Breaker Contact State Assessment Method Based on Live Dynamic Resistance Measurement

The state of the circuit breaker contacts has an important influence on their arc extinguishing performance. Dynamic resistance measurement is an important means to evaluate the state of the contacts, but it can only be performed in a power-off state, which greatly limits its application. To this end, this paper provides a method for online measurement of dynamic resistance. The basic principle of measurement is introduced, and a research platform is established in the laboratory to measure the dynamic resistance of contacts with different degrees of ablation. The research results show that the time when the dynamic resistance peak appears is closely related to the degree of ablation of the arc contact. The proposed method for measuring the energized dynamic resistance can effectively reflect the degree of ablation of the circuit breaker contacts.