Advanced slip mode frequency shift islanding detection method for single phase grid connected PV inverters

This paper presents an active islanding detection method which has zero non-detection zone. This method is the advanced version of the conventional slip mode frequency shift islanding detection method (SMS IDM). In this method the parameters of SMS IDM change based on the local load impedance value. The parameters value are calibrated periodically by measuring the impedance of the local load. The local load impedance can be calculated by injecting harmonic currents to the point of common coupling (PCC) and measuring its voltage during the calibration period. Simulation and experimental results show the accuracy of the proposed method in detection of islanding in any loading conditions.