Modularized Power-Electronic Buck Converter based High-Power Impulse Current Test Circuit - Comparative Analysis of Simulation and Experiment

Extended low and medium voltage direct current applications, systems and grids are gaining increasing focus in research and development. Their safe and reliable operation is a prerequisite for a sustainable penetration of these technologies. In this regard, the interruption of dc currents in the event of a fault is one of the key challenges. Since fault currents in dc systems fundamentally differ from those in ac systems, readily available ac switching equipment cannot be applied in future dc grids. Therefore, the degree of availability of adequate dc switching equipment significantly hinders, respectively enables, the realization of extended low voltage dc and medium voltage dc grids. The development of such dc switching equipment requires a deep understanding of physical phenomena during a current interruption process in dc systems. Besides the simulative rep-resentation of such phenomena, experimental investigations are indispensable. However, well-established high-power test circuits, which conventionally focus on ac investigations, cannot be used for realistically representing the associated stresses. For this rea-son, an innovative high-power testing and investigation approach for the analysis of dc circuit breakers and dc arc phenomena is presented. The developed high-power test circuit is based on the functionality of a modularized power-electronic buck converter (PEBC). This paper details the setup and highlights the functionality in a demonstrator test bench. The focus is put on the comparative analysis of simulation and experimental results of the developed test bench. As a result, a validated black box simulation model is available as a design instrument for analyses of the high-power test circuit behavior in consideration of future use cases and devices under test.