Study of Anomalous Breakage of Closing Resistors of Circuit Breakers for 750 kV AC Filter Fields

Closing resistors are mainly used in line circuit breakers of 800 kV and above and AC filter circuit breakers of 550 kV and above to suppress the closing inrush current and transient overvoltage during the closing process of circuit breakers. Due to the special characteristics of its operating conditions, it needs to be cast and cut frequently, resulting in frequent failures of the closing resistor piece. In this paper, the electric field and modal simulation model of the closing resistor stack is established. Simulation results show that when the closing resistor is broken, the electric field around it produces distortion, which is 39% higher than the normal working condition, harming the normal operation. Modal simulation results show that the resonance frequency of the resistor stack in the first 6 orders is 18.7–43.37 Hz, which is close to the intrinsic frequency of general trucks and vans, and the vibration should be reduced as much as possible to avoid resonance of the resistor stack in the transportation process to ensure the reliability of the product.