An islanding detection method based on system identification

Islanding detection is a crucial technique for distributed generation(DG) system in case that a grid is still energized by DG when it is cut off. In this paper, an islanding detection method based on system identification is proposed. Regarding the grid as a RLC load, a recursive least square(RLS) method is used to obtain estimated parameters of the the equivalent RLC. Different from other system identifications, our algorithm adjusts the traditional RLS, concerning on the tiny change of parameters. Two parameters reflecting the change of the equivalent system are proposed for a decision of whether DG is disconnected from the grid or not. a simulation experiment demonstrates that the algorithm is effective and fast for detecting islanding event.