Modelling and simulation of a high-voltage direct current ballistic circuit breaker

Interrupting a DC high power line is a very challenging task since the key element that greatly simplifies the problem in a similar AC case, which is the zero crossing of the current, is missing. The consequence of the current interruption is the occurrence of an electrical arc which must be safely extinguished. In HVDC (high-voltage direct current) applications the currents that need to be interrupted have very large values and, in addition, the power lines have a notable inductance making the extinguishing operation a serious issue if the breaking is done directly to open circuit, especially if there is a short circuit type of fault at the consumer end of the power line. A ballistic breaker gradually introduces resistors in series with the load, avoiding troublesome large current jumps, in order to achieve a smoothly interruption. Since this type of circuit breaker is relatively new, introduced in 2011, its modelling and simulation is still an up-to-date topic. The paper presents two models for a ballistic breaker, one MATLAB-Simulink model and one SPICE model which can be used to investigate and perfect the device, and also presents the simulation results for various parameters and implementation variants, highlighting strengths and weaknesses.