This paper proposes a novel hybrid approach for islanding detection ofinverter-based distributed generations (DG) based on combination of the Slipmode frequency-shift (SMS) as an active and rate of change of frequency (ROCOF)relay and over/under frequency relay as passive methods. This approach isutilized to force the DG to lose its stable operation and drift the frequencyout of the allowed range of the frequency threshold. Performance of theproposed approach is evaluated under the IEEE 1547, UL 1741 and multiple-DGoperation. The simulation results demonstrate the effectiveness of the proposedapproach for detection of islanding, especially for loads with high qualityfactor. It operates accurately under the condition of load switching and doesnot interfere with the power system operation during normal condition. In otherwords, not only it holds the benefits of both SMS and ROCOF, but also itremoves their drawbacks by having less non-detection zone and faster response.
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