Contact Resistance as an Indicator of Arcing Contact Degradation in High-Voltage Gas Circuit Breakers

Electrical life of arcing contacts determines the reliability and service lifetime of high-voltage gas circuit breakers. After current interruptions, it leads to an electrical degradation of the interrupting unit, which is typically referred to as contact erosion. Material transfer occurs between the plug and tulip contacts of the circuit breaker due to a splash erosion. Thus, mass loss, as a conventional characterization parameter, cannot represent the erosion degree of the tulip contact. Therefore, to characterize the degree of arc erosion scientifically, contact resistance is adopted as a basic parameter in this study. It has been found that the transferred charge or arc energy can be used as variables to quantitatively study the degradation process of the contact resistance of arcing contacts. The development of contact resistance at different stages can be explained through the material testing of contact surface. The research in this contribution can be applied to the condition monitoring and evaluation of the contact system, which provides scientific guidance for improving the reliability of gas circuit breakers.