Theoretical Analysis and Calculation of Arc Contact Erosion of High Voltage Circuit Breaker

Arc contact condition is the determinant factor that influences the electrical lifetime of high voltage circuit breaker and the decrease of electrical lifetime means the deterioration of insulation and opening capacity of arc distinguishing chamber. Present prediction method of electrical lifetime cannot directly obtain the condition of arc contact. In this paper, the short-circuit current is generated by the circuit breaker synthesis test circuit to simulate the erosion of the arc contact during the opening operation. The contact travel throughout the erosion tests has been measured by dynamic resistance measurement (DRM). The decrement of contact travel for each erosion test with the same opening current and arc time is constant. The calculated value of contact travel decrement (0.27mm) for each erosion test is close to the measured value (0.32mm) based on contact erosion theory.