Influences of Arcing Time and Initial Pressure of the Puffer Chamber on Asymmetric Short-Circuit Current Interruption Performance of High-Voltage SF6 Circuit Breakers

With the continuous increase in grid capacity and the rise in the time constant of the DC component of short-circuit currents in power systems, the hidden dangers of insufficient interrupting capability of circuit breakers have become increasingly prominent. Therefore, it is crucial to study the factors affecting the interruption performance of circuit breakers. The article establishes a physical arc simulation model based on the internal structure of high-voltage SF6 circuit breakers, and investigates the effects of the time constant of the DC component of short-circuit currents, arcing time, and initial pressure of the puffer chamber on the interruption performance of the circuit breakers. The results show that increasing the arcing time and initial pressure of the puffer chamber facilitates circuit breaker interruption, while an increase in the DC component tends to lead to interruption failure. These findings provide a theoretical basis for improving the capability of high-voltage circuit breakers to interrupt asymmetric short-circuit currents.

I. Introduction

In recent years, as grid capacity has continued to increase, the ratio of reactance to the resistance of various power equipment has also gradually increased, leading to a rise in the time constant of the DC component of short-circuit currents, far exceeding the standard time constant of 45 ms. This results in the increasingly prominent hidden dangers of insufficient interrupting capability of circuit breakers, becoming a major issue in current grid development [1],,[3]. Therefore, it is of great significance to study the factors affecting the interruption performance of circuit breakers.