COMPUTER SIMULATION OF THE ARCING PROCESS IN HIGH VOLTAGE PUFFER CIRCUIT BREAKERS WITH HOLLOW CONTACTS

Issues associated with computer simulation of high voltage puffer circuit breaker arcs burning between two hollow contacts are discussed and several test cases modelled with a two dimensional axisymmetric arc model. The unrealistic influence of Lorentz force associated with the uncertainties in arc rooting on the shape of arc column and arc voltage is demonstrated and its cause argued based on arc voltage measurement. The concept of transparent arc root is introduced to suppress the unwanted arc column contraction. Reasonable agreement between predicted and measured arc voltage is obtained for high current arcs. Effort is also made to simulate the extinction peak shortly before the final current zero.