A Combined Electronic Overvoltage and Overcurrent Protection Concept

Electronic overcurrent fuses and surge protective devices (SPD) are widely used to protect DC-grids supplying mobile stations or industrial systems. The separation of the two protection functions goes along with disadvantages in the field, such as coordination problems between the electronic overcurrent fuse and the SPD, e.g. false tripping of the electronic fuse during an overvoltage event and longer failure times. This paper presents a concept to combine the overcurrent and overvoltage protection in a single device by using power electronics to realize both functions. By their combination it is possible to distinguish between different failure situations what leads to a higher system availability. Furthermore, it is possible to implement a wider protection concept. Low protection levels guarantee a larger protection area and protection against temporary overvoltage (TOV) can be achieved with this concept. Higher nominal currents for SPDs are possible as no inductive or resistive decoupling is needed.