Combined model of SF6 circuit breaker for use in digital simulation programs

The paper describes a combined model of the high-voltage SF₆ circuit breaker for digital simulations. The model is intended for detailed simulations of switching transients in electrical power systems in cases where interaction between physical phenomena in the circuit breaker and the system plays important role. The circuit breaker model is a black-box model introduced in the modeled system as a two-pole element with a variable impedance. The value of impedance is determined by a regulator dependent on a mathematical model. It consists of four partial models: a closed circuit-breaker model, a burning arc model, a current zero crossing model, and an open circuit breaker model. All four models are used in the same simulation sequence. The developed model can be used for various simulations as a one-phase model or as a three-phase model. In the paper, the model performance is verified and its practical applications are shown.