Identification of Relevant Fault Types for Grid Planning of DC Distribution Grids

Inhalt:
For DC distribution grids no standards regarding fault currents and relevant fault types exist. Therefore, the aim of this paper is to identify relevant fault types for a fault current analysis as part of DC distribution grid planning. DC faults can typically be fed by two sources, namely the discharge of grid internal capacities as well as feeding of AC grids and generation units over converters. The fault current contribution over converters differs for different converter topologies. Thus, the behavior of commonly used converter topologies during a DC fault is presented in this paper. Simulations have been conducted for different fault types in a point-to-point medium voltage DC connection. Thereby, relevant fault types leading to significant stresses of grid equipment and installations are identified for different branch configurations.