Design and Development of a Short-Circuit Test Bench for Low-Voltage Direct Current Protection Devices

In this paper, the design and development of a short-circuit test bench for LVDC protection devices will be presented. The popularity of LVDC microgrids is increasing due to the better compatibility with DC loads, DC storage and DC generation. However, the protection of these grids remains one of the key hurdles to be overcome before a further industrialization is possible. An important aspect to be considered is the fact that the testing procedures that are described in today's standards do not align with the short-circuit currents that are encountered in converter dominated LVDC grids. The standard IEC test procedures are based on a strong, inductive LVDC grid. However, a converter dominated LVDC grid is more capacitive than inductive and the short-circuit currents that flow contain a fast transient peak that might go unnoticed. Therefore, a test bench was developed to test LVDC circuit breakers under realistic fault conditions.