Subtransient Fault in a DC Distribution Network with Considering Upstream Grid

The increasing demand for DC loads in distribution networks is reshaping modern power systems toward DC. One of the main challenges in distribution networks is protection, especially due to the high subtransient fault currents caused by the energy discharge from capacitors in converters. Accurate fault behavior identification is the first step in providing appropriate protection for these networks. This paper focuses on calculating the peak fault current resulting from the discharge of capacitors in converters. Simulations have been conducted on an ideal 9-bus network. The results have been compared for two fault locations: one at the corner and the other at the center of the network. Additionally, the impact of the upstream network on the fault current formation has also been considered in this study.