This paper proposes a novel hybrid islanding detection method for inverter-based distributed generation based on frequency drift. This algorithm is a combination of Sandia frequency-shift (SFS), reactive power versus frequency (Q-f) and reactive power deviation (RPD) as active methods and under/over frequency protection (UFP/OFP) as a passive method. The performance of the proposed method is evaluated under the UL 1741 anti-islanding tests configuration, IEEE 1547, Load switching, Load quality factor and multiple-DG operation. The simulation results are derived by MATLAB/Simulink. Based on simulation results, it is clear that the proposed method is developed to detect islanding more efficiently for loads with high quality factor. The proposed method also has less NDZ comparing other methods. In addition, the proposed method operates accurately in condition of load switching while does not interfere with the power system operation during normal conditions. This technique proves to be robust under multiple-DG operation.
