Requirements on Surge Protective Devices in Modern DC-Grids

The paper gives an overview on the forthcoming requirements that surge protective devices (SPD) will face in modern DC-grids. Therefore, the current and future structure of DC-grids which is under discussion will be analysed. Based on the characteristics of modern DC-grids the required protection levels, the behaviour of possible follow currents and the maximum surge current discharge capacity needed in DC-grids will be investigated. Furthermore, this work shows the requirements on SPDs protecting the DC grid from transient overvoltages with regard to their withstand capability to temporary overvoltage in DC-grids caused by power crossing events and fault situations.