Modeling the DC Circuit Disconnection by a Circuit Breaker

The article describes the development of a mathematical model for simulating the disconnection of DC circuits in the absence of experimental data for studying the dynamics of transients. The stages of the circuit disconnection process by a circuit breaker are given, and it is noted that the voltage across the arc has an effect on the process pattern. In carrying out the simulation, the averaged dependence of the arc voltage obtained from the waveforms of clearing a short-circuit fault by a circuit breaker is used. The possibility of describing the circuit disconnection process by the Duhamel integral is shown, where the current is the system response to the disturbance in the form of an arc voltage having a complex waveform. As a result, an expression in general form is obtained, using which it is possible to calculate the entire transient of disconnecting the circuit by a circuit breaker for any waveforms of opposite voltages across the arc and with various methods of approximating them at each time interval considered. The article also gives an example of calculating the short-circuit current cleared by a high-speed circuit breaker of the KVR series, with a piecewise linear approximation of its dependence on the arc voltage, which makes it possible to assess the mathematical model adequacy.