自触型低压混合式直流断路器系统设计与开断特性研究

The low voltage hybrid DC circuit breaker has the advantages of low power consumption, high breaking performance and selective protection, which can better meet the new development needs of photovoltaic, energy storage systems and zero carbon buildings. In this paper, a self-triggered low-voltage DC hybrid switch topology is proposed. First, through the analysis of the working principle of the hybrid circuit breaker, the electromechanical-coupling design method based on arc power supply and drive is proposed. This method uses the arc energy to supply energy to the electronic circuit, and uses the arc voltage as the control signal for the conduction of the converter branch to realize the automatic triggering of the system under short circuit fault. And the theoretical basis for the design of core functional modules is described. On this basis, a low voltage hybrid circuit breaker prototype is developed and the feasibility of the scheme is demonstrated. Finally, the influence rules of different factors on the breaking characteristics are compared and analyzed. Experiments show that compared with the traditional mechanical switch, the little current breaking time is reduced by 85.4%, and the arc energy is reduced by 94.1%, which improves the service life of the circuit breaker, and can successfully break 1.1 kA short-circuit current. It is pointed out that the overall response time of the system is positively related to the voltage rise rate at the initial stage of arcing. The increase of arc conductance and branch parasitic inductance will extend the commutation time. The arc reignition probability is mainly affected by the external system parameters. It may provide basis for the optimization design and performance improvement of low-voltage DC hybrid circuit breakers.