An Islanding Detection Method for Multi-RES Systems Using the Graph Search Method

An islanding operation refers to the phenomenon in which a part of a power system composed of one or more power sources and loads is separated from the rest of the system for a certain period. An unintentional islanding operation may cause system instability and lead to human accidents, so it should be detected to prevent problems. Conventional various methods for determining islanding operation detect the islanding through the variation of power quality. However, these methods may not operate correctly in a power system which includes a variety of devices that improve power quality in the future. Therefore, in this study, we propose a method of determining islanding operation based on system configuration. Connection status between Renewable Energy Sources (RESs) and main source can be checked using depth first search among the graph search method. If RESs and main sources are connected, it is not an islanding operation and vice-versa. The simulation results show that the proposed islanding detection method complies with the maximum detection time of IEEE Std. 1547.