177 / 2024-04-15 16:44:33

Investigation of the equivalent circuit model of post-arc sheath stage in DC vacuum circuit breakers

DC Vacuum Circuit Breakers, Equivalent Circuit Model, PIC-MCC Simulation, Post-Arc Sheath, Post-arc Current

This paper proposes an equivalent circuit model of the post-arc sheath stage in DC vacuum circuit breakers and outlines the method to calculate the circuit parameters from Particle-in-Cell Monte Carlo Collision (PIC-MCC) simulation results. The ion sheath is treated as a parallel connection of a resistor and a capacitor, while the plasma region between the sheath edge and post-arc anode is modelled as a resistor whose resistance is small enough to be ignored. A PIC-MCC model is developed to provide plasma parameters and electric field information for calculating the values of resistance and capacitance of the equivalent circuit. Through appropriate simplifications, these parameters from PIC-MCC simulations are applied to the conductivity equation and capacitance equation to finally obtain values of circuit parameters, which are resistance and capacitance values, at different times. By applying transient recovery voltage (TRV), the total current flowing through the resistor and capacitor at the corresponding moment is computed with the obtained circuit parameters. Reasonable agreement between the simulated post-arc current waveform and experimental results confirms the feasibility of the proposed equivalent circuit model and the circuit parameter calculation method.