Fuses in distribution systems: new applications in DC circuits

The vast majority of distribution systems currently in use, work with alternating current at 50 Hz or 60 Hz. Several of the distributed resources (generators or storage) supply electrical energy in the form of direct current. Also, there are continuous end-use applications such as centralized variable speed drives, and the rapidly growing application in electric cars which has recently started. This panorama leads to the growing interest in the application of fuses in direct current systems, not as an adaptation of the alternating current fuse but as a specific design. The article presents the crucial differences between direct and alternating circuits, oriented to the operation of the fuse, highlighting their advantages and disadvantages, citing the complications in the design that are required for this growing application. The continuous operation of the fuse is explained in its three fundamental parts: pre-arc, arc and post-arc. The most important current applications are analyzed, such as the protection of: circuits with batteries, circuits of electric vehicles for individual use, power electronics, photovoltaic cells, public transport and circuits in mining. It is concluded in the need to deepen the study of these applications in order to achieve specific fuses designs for direct current and not mere adaptations of the traditional alternating current fuse designs.