Pre insertion resistors are an important component of circuit breakers

playing a protective role by suppres sing operating overvoltage and closing inrush currents.However

they experience a high failure rate during operation.This study calculates the electrical parameters based on the structural design of the pre insertion resistors and constructs a simulation model for the equivalent impedance parameters of the circuit breaker’s closing resistance

using an RLC circuit as the basic unit.The study explores the variation in the closing resistance impedance parameters under different damage conditions.The results show that for closing resistors with damages such as blackening

burning

cracking

and edge detachment

the high frequency impedance characteristic curves exhibit clear differences compared to the normal resistance curve.These results validate the feasibility of using high frequency impedance technology for diagnosing damage to the closing resistors.This research provides valuable insights for the future development and optimization of damage detection systems for circuit breaker pre insertion resistors based on high frequency impedance.