Relationships of expansion volume and arcing characteristics at large current interruption

As one of the key factors, the relationships of expansion volume and arcing characteristics have been treated importantly for the design and optimization of gas circuit breakers. In the paper, a simple 145kV auto-expansion circuit breaker model is adopted. With the method of MHD, arcing process under three different expansion volumes at large current 60Hz interruption is simulated. The contours of gas pressure, gas temperature and gas velocity around current zero are given. The physical quantities at the instants under the different expansion volumes are compared. Furthermore, the characteristics of arc plasma affected by the expansion volumes are discussed and the more suitable size of the volume for the interruption under the current 36kA is obtained.