Minimum Fault Current Limiter Reactance Determination Algorithm for MVDC Protection in Hybrid AC/DC Distribution Systems

The increasing deployment of renewable energy sources, ultra-fast electric vehicle charging infrastructure, and energy storage systems has brought growing attention to AC/DC hybrid distribution networks that integrate medium-voltage direct current(MVDC) systems. However, DCnetworks exhibit fault characteristics and protection requirements that differ substantially from those of conventional AC systems, making their protection more challenging. To enable reliable protection in AC/DC hybrid distribution grids, it is essential to design fault current limiters(FCLs) that account for the fault protection conditions of the embedded DC network. This paper proposes an algorithm for determining the reactance of an FCL applicable to DC circuit breaker-based protection schemes. Using EMT simulations on an MVDC test system, we verify that the proposed algorithm successfully determines the appropriate FCL reactance that satisfies the protection requirements of the DC network.