Research and Experiment on Temperature Characteristics of a Fast Mechanical Switch Drive Circuit for Hybrid DC Circuit Breaker

The fast mechanical switch is the core component of the hybrid DC circuit breaker. Under actual working conditions, the fast mechanical switch should be able to work reliably. In this paper, the circuit stray parameters of the pre-charged capacitor in the fast mechanical switch drive circuit to discharge the fast mechanical switch opening coil are extracted by finite element simulation software. Under the temperature condition of -20 °C ~ 80 °C, the fast mechanical switch drive with aluminum electrolytic capacitor and polypropylene film capacitor was tested respectively, and the parameter changes of aluminum electrolytic capacitor in the drive circuit under different temperature conditions were obtained. The results show that the equivalent series resistance ( ESR ) of the aluminum electrolytic capacitor is negatively correlated with the ambient temperature. When the ambient temperature is lower than 0 °C, the ESR of the aluminum electrolytic capacitor increases significantly. At this time, the fast mechanical switch drive using aluminum electrolytic capacitors will lead to the failure of the fast mechanical switch opening. In contrast, the fast mechanical switch drive using polypropylene film capacitors has better low temperature characteristics.