A Complete Strategy for Conducting Dynamic Contact Resistance Measurements on HV Circuit Breakers

Dynamic contact resistance measurement (DRM) is known as an effective technique for assessing the condition of power circuit-breaker (CB) main contacts and arcing contacts. In some SF 6 gas CBs, the metallic fluorides (white or gray powder) produced during the arc quenching process mask the actual breaker contact resistance. In this case, the standard DRM method of injecting 100 A dc is no longer applicable. The following paper proposes a complete strategy for conducting DRM on high-voltage CBs based on three relevant parameters: breaker contact speed (low or rated), injected current values (100-2800 A dc), and the presence of metallic fluorides deposited on breaker contacts.