This paper proposes a new islanding detection method for use in a small-scale, grid-interconnected distributed generator system. The proposed islanding detection method is based on voltage fluctuation injection, which can be obtained through high-impedance load switching on the grid periodically. The correlation factor between the periodic switching signal and the perturbed voltage is then used as an islanding detection index in the proposed islanding detection method. Experimental results demonstrate the principles of the proposed technique.

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