A new active island detection method which is based on a novel disturbance way

Island will not only lead a damaging to the equipment of the power system, serious when, may appear a series of problems like threatening the safety of the maintenance personnel of the power system. So the grid-connected Photovoltaic power generation system must have the function of detecting the islanding in all the time to ensure if the gird is working. The traditional AFD´s detecting effects are different under different kinds of loads, it´s better for the impedance load, but it brings a high THD. Although researchers proposed the improved AFDs based on the feedback adjustment or periodic disturbance which could reduce the THD, but they slow down the detecting speed at the same time. In view of this, this paper proposes a new active island detection method which adopts a novel disturbing way with low THD, and the detection effects are better than the traditional AFD under RLC impedance load. The non-detection zone is smaller and the detecting speed is faster, better yet, the THD injecting to the grid is lower, it has a practical value. In this paper, Matlab/Simulink simulation experiment shows that the proposed method is better than the traditional AFD at reducing THD, improving the detecting speed, and reducing the non-detection zone.