Numerical simulation of vacuum arc and anode thermal process during the interruption process of HVDC vacuum switch with forced current zero

It is of great significance to study DC vacuum arc (DCVA) characteristics and anode thermal process in DC interruption based on artificial current zero method, which have great influence on the breaking performance of DC vacuum circuit breaker (DCVCB). In this paper, with the consideration of the effect of realistic magnetic field and hysteresis during the DC breaking process, the dynamic characteristics of DCVA and anode thermal process were simulated and analyzed. Firstly, a DCVA dynamic model is established under the commercial cup-shaped electrodes. The DCVA characteristics at seven different moments during the DC breaking process with a current falling frequency of 1kHz were simulated, which were combined to describe the dynamic characteristics of DCVA. The distribution of arc plasma’s parameters at seven different times, such as ion pressure and axial current density, was obtained by the simulation. Furthermore, a 2-D transient axisymmetric model of anode thermal process in DCVA is established. Through the numerical simulation, anode temperature distribution along radial and axial directions during the DC breaking process can be obtained.