Multiphysics Simulation Analysis of Excessive Circuit Resistance of Reactive Power Compensation Circuit Breaker

In order to analyze the reasons for the excessive resistance of reactive power compensation SF6 circuit breaker in actual switching scenarios, firstly, the overvoltage and surge current situations during the switching process of shunt capacitor bank were simulated in this paper. Then, based on overvoltage and surge current data, a multi physics field simulation was conducted on the electromagnetic field, temperature field, and fluid field coupling of the arc chamber. The results show that the reignition overvoltage generated during the disconnection process of the shunt capacitor bank can reach up to 6 times the rated voltage of the system, and the surge current generated during the connection of the shunt capacitor bank can reach up to 16.8 times the rated current, which has a significant impact on the stable operation of the circuit breaker. The surge current generated during the connection process can cause temperature rise, with a maximum temperature close to 1000K. The reignition arc will burn the contact, and the maximum temperature of the contact can reach 7875 K. All of these situations will have an impact on the electrical contact performance of the contacts, which will cause the resistance of breaker circuit to exceed the standard.