Islanding Detection Method for Inverter-Based Distributed Generation by Injecting Second Order Harmonic Current

Abstract

This paper proposes a new islanding detection scheme for the inverter-based distributed generator by injecting negligible amount of the 2nd order harmonic current. A proportional resonant controller was used for the output current control of the inverter, and a proportional resonant filter was used for extracting the 2nd order harmonic voltage at the point of common coupling (PCC). The islanding state can be detected by measuring the magnitude ratio of the 2nd order harmonic voltage to the fundamental voltage when the 2nd order harmonic current with 0.8% magnitude is injected.