Breaker-Less MVDC-Grid with Single-Phase Dual-Active Bridge

With the growing importance of renewable energy sources, including photovoltaic systems, electric vehicles, and energy storage solutions, a significant transformation in the electrical energy supply structure from centralized to highly decentralized systems is needed. DC-based systems promise reduced system costs and increased efficiency by eliminating multiple inefficient conversion steps. One significant challenge, which limits the spread of MVDC grids, is the protection against grid faults. While hybrid and solid-state circuit breakers present possible remedies, the breaker-less dc grid emerges as a compelling option due to its elimination of extra components, leading to cost savings and unhampered operation during regular use. A key point to realizing this alternative is understanding the behavior of dc grid faults. For this, a short circuit test was carried out on a 2.3 km, ±2.5 kV MVDC ring grid to determine the fault current handling capabilities of a single-phase dual-active bridge converter. The results show the feasibility of the breaker-less dc grid in real-world MVDC grid.