부산대학교 도서관

An increasing number of electrical loads and sources in the distribution grid require a conversion step from DC, or AC at variable frequency, to be connected to the traditional 50/60Hz AC grid. This sparks an increasing interest for Low Voltage DC microgrids as an alternative. LVDC grids enable a reduction of the losses and an increase of the transfer capacity compared to their AC equivalent. However, fast and selective fault protection still remains a major obstacle for the breakthrough of LVDC grids. The challenge is twofold: On the one hand, a protection strategy for fast fault identification is required, on the other hand there is a need for protection devices capable of fast fault clearance in an LVDC grid. This paper first gives an overview of the current state-of-the-art of fault indicators and methods for fault identification in DC grids, addressing the first part of the challenge. Subsequently, an overview is given of the interruption devices that are currently available for fault clearance in DC grids and their (dis)advantages, addressing the second challenge.