Experimental verification of a new positive feedback islanding detection method for grid-connected inverter

Abstract

Islanding detection is one of the most importantissues for grid-connected inverter applications. A new positive-feedbackanti-islanding method is presented in this paper. It utilizes the negativesequence voltage component as a positive feedback variable, and no additionalnegative sequence disturbance is needed at all. After islanding, the positivefeedback loop will force the negative sequence voltage component away from thenominal value. A new negative sequence estimation algorithm is alsopresented for the successful islanding detection. Finally, the experimental testsare carried out to verify the effectiveness of the proposed method.