Interruption of MVDC currents with HV fuses

Direct current (DC) power grids are gaining importance due to their efficiency in long-distance power transmission and reduced losses. High voltage direct current (HVDC) technology enables grid stabilization, the ability to interconnect networks that are asynchronous or operate at different frequencies. Its improved controllability plays a key role in the integration of renewable energy sources and in meeting the challenges of the modern electricity grid. However, these advantages come with challenges, particularly in fault current interruption. In contrast to alternating current (AC) systems, where the current naturally crosses zero, making fault interruption more straightforward, DC circuits lack this inherent zero-crossing point. This characteristic makes it more difficult to interrupt fault currents, so advanced solutions are needed to ensure the safe and reliable operati on of DC systems. This paper addresses the critical need for advanced fault current protection in DC grids. High-voltage (HV) fuses are explored as a promising solution for protecting DC systems by enabling reliable and efficient fault current interruption. Key innovations, such as reducing minimum breaking current (Imin), increasing operating voltage, and achieving compact fuse designs, are discussed, supported by experimental results.