Fault Self-Healing Method for Flexible-Ac-Port Solid-State Transformer

The Enhanced Soft Normally Open Point (eSNOP) equipped with DC ports enables the integration of DC sources and loads into AC grids while facilitating flexible control of multi-port power flow, reactive power compensation, and other functionalities. However, existing e-SNOP topologies typically adopt full-power schemes, which result in high costs and large physical dimensions, limiting their widespread application. To address this limitation, this paper proposes a topology based on a Flexible AC Port Solid-State Transformer (FACP-SST), featuring advantages such as low cost, compact size, and convenient port expansion. Nevertheless, due to the absence of electrical isolation inherent in conventional transformers, short-circuit currents from non-faulted feeders may flow into faulted feeders during AC line short circuits, causing a sharp increase in short-circuit current at the faulted port and potentially affecting the operation of other ports. To tackle this challenge, this paper presents a fault self-healing method specifically designed for FACP-SST. This method enables rapid isolation of faulty feeders while allowing healthy feeders to maintain normal operation. The configuration and implementation of this solution are discussed in detail, and its effectiveness is validated through simulation results.