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.

中文翻译：

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图搜索法的多RES系统孤岛检测方法

孤岛操作是指一种现象，其中由一个或多个电源和负载组成的电力系统的一部分在一段时间内与系统的其余部分分开。意外的孤岛操作可能会导致系统不稳定并导致人身事故，因此应进行检测以防止出现问题。用于确定孤岛运行的常规各种方法通过电能质量的变化来检测孤岛。但是，这些方法在包括将来会改善电能质量的各种设备的电力系统中可能无法正确运行。因此，在这项研究中，我们提出了一种基于系统配置确定孤岛运行的方法。可以使用图形搜索方法中的深度优先搜索来检查可再生能源（RES）和主电源之间的连接状态。如果连接了RES和主要信号源，则不是孤岛操作，反之亦然。仿真结果表明，提出的孤岛检测方法符合IEEE Std的最大检测时间。1547。