SCR-Based Bidirectional Circuit Breaker for DC System Protection With Soft Reclosing Capability

The emergence of power electronics has lead to a paradigm shift toward dc grids, which are widely recognized to provide better performance and efficiency. However, fault isolation is one of the prime challenges of dc grids due to the absence of current zero-crossing. With this motivation, this article introduces a novel silicon-controlled-rectifier-based bidirectional dc solid-state circuit breaker. In addition to its ability to isolate the faulty section, the proposed topology can also provide soft reclosing capability, which aids in reducing repetitive voltage and current stress on the breaker and current feeding components. Moreover, the heat loss by the surge suppression devices during reclosing is negligible. Equations are derived to analyze the effect of component values on various circuit-level considerations. Simulation and scaled-down experimental results are presented to verify the operation of the breaker under various operating conditions.