Interruption characteristics of self-powered hybrid DC circuit breaker with synergistic effect of step-down and divided current

•The DC side voltage level of the system has been continuously improved in PV and PEDF system, it has developed towards DC3000V. This puts forward new requirements to higher voltage (>DC1500 V) DC circuit breakers for DC side short-circuit fault protection. Based on this, a self-powered hybrid DC circuit breaker with synergistic effect of step-down and divided current is proposed, which uses the voltage of the main branch to trigger IGBT conduction that can achieve commutation without additional trigger circuit. The interruption characteristics is analyzed by simulation. The voltage division of the reactor and the shunt function of the shunt resistance during the fault breaking process can not only reduce the current peak of the main branch and the transfer branch, but also greatly reduce the voltage that the mechanical switch needs to withstand, reduce the probability of post-arc reignition, and shorten the interruption time of the circuit breaker. The circuit breaker topology proposed in this paper can realize the interruption of the DC arc at larger fault current and higher voltage. It provides guidance for hybrid DC circuit breaker used to complete fault interruption in renewable energy power systems. The DC voltage level of photovoltaic and PEDF applications have continuously advanced, reaching up to DC3000V. This presents new requirements for DC circuit breakers operating at higher voltages (>DC1500V) to ensure effective fault protection in the DC side. Based on this, a self-powered hybrid DC circuit breaker with synergistic effect of step-down and divided current is proposed. This innovative design utilizes the voltage of main branch to trigger IGBT conduction, eliminating the need for an additional trigger circuit. The interruption characteristics is analyzed by simulation. The reactor and shunt resistance effectively reduce the peak currents of both main and transfer branches. This approach significantly mitigates the voltage stress on the mechanical switch, reduces the risk of post-arc reignition, and shortens the interruption time. The circuit breaker topology proposed enables the DC arc interruption at larger current and higher voltage, serving as the valuable guide for the implementation of hybrid DC circuit breakers in renewable energy power systems.