Analysis of Fault Current Characteristics and its Suppression Methods Study in DC Microgrid

With the rapid development of AC/DC power distribution network, DC microgrids will become an important part of the future power distribution network. The DC microgrid has a small coverage area and a small line impedance. When the bipolar short circuit occurs, the fault current can reach a rated operating current of more than ten times, causing a serious impact on the system. In this paper, the fault current characteristics and generation mechanism of photovoltaic power system branch, battery energy storage branch and AC power interface branch are studied respectively. According to the characteristics of each branch's fault current, different fault overcurrent suppression methods are proposed for each branch. And the effectiveness is verified by simulation analysis at finally. The fault current suppression method proposed in this paper is directly targeted at the characteristic and mechanism of fault current generation. It has the characteristics of strong pertinence, simple implementation, low cost and high application value.