<p>To overcome the limitations of traditional transformers, such as their low power density relative to weight and volume, intensive research on solid-state transformer (SST) system has been actively conducted worldwide. In particular, leading global railway companies are exploring the application of SST systems to railway vehicles with large-scale loads, and various topologies are being proposed. However, because railway vehicles operate in connection with larger system, the interface between the system and vehicle is crucial. System faults can result in significant operational losses, making full-scale testing impractical. Therefore, the behavior of solid-state transformers under power system faults must be pre-analyzed through simulations. This study analyzes the interface characteristics of SST system for high-speed railways under system fault conditions. After modeling both the railway power supply system and SST system, a ground fault, which represents one of the major failure types in the railway power system, was assumed as the fault scenario. The results were analyzed through simulation based on the vehicle and fault locations. The results of this study are expected to serve as valuable data for the stable operation of railway vehicles equipped with SST system.</p>