To overcome the limitations of conventional islanding detection methods, including large non-detection zones (NDZ) and power quality degradation, this paper proposes a hybrid method combining empirical mode decomposition-Hilbert-Huang transform (EMD-HHT) and adaptive active power disturbance. The passive method uses EMD-HHT to extract the instantaneous frequency of the first intrinsic mode function (IMF1) from the voltage at the point of common coupling (PCC). The active disturbance is activated only upon islanding detection by the passive method, computed in real-time using voltage and power data to drive the PCC voltage beyond over-voltage protection (OVP) and under-voltage protection (UVP) thresholds. This method eliminates the NDZ without requiring continuous disturbances, reducing impacts on power quality. PSCAD/MATLAB simulations show that the method achieves accurate islanding detection within 40 ms under both power-matched and ±5% active power mismatch conditions, and there is no misjudgment during normal power grid voltage fluctuation.
Jia et al. (Sun,) studied this question.