A physical arc model for the simulation of current zero behavior of high-voltage circuit breakers

The interrupting capability of SF₆ circuit breakers has increased drastically during the last decade. After the development tests, high-voltage circuit breakers are tested in the high-power laboratory, where test conditions prescribed by standards and switching conditions in electrical transmission networks are simulated. It is important that the test circuits used in the laboratory give a correct representation of the current and voltage stress. The equations and parameters of a physical arc model are presented which can be used to compare test circuits with respect to the thermal and dielectric interrupting interval of SF₆ circuit breakers. An example calculation with the alternative transient program (ATP) shows the interruption of a terminal fault with a 4-parameter TRV. The sensitivity of the arc model in the thermal interrupting interval is demonstrated by comparing artificial line circuits