Gibbs Phenomenon-Based Hybrid Islanding Detection Strategy for VSC-Based Microgrids Using Frequency Shift, $THD_{U}$ , and $RMS_{U}$

One of the most crucial problems in distribution networks (DNs) is islanding detection. This paper presents a new Gibbs phenomenon-based hybrid method for islanding detection in low voltage (LV) DNs based on a combination of active and passive methods of frequency rate of change at a given moment and measurement of constant total harmonic distortion (THD). The proposed method exploits Gibbs phenomenon occurring at the interpolation of sinusoidal functions. Beside identification of Gibbs phenomenon, root mean square of the voltage is tracked in parallel with THD
_U
for firm islanding detection. Finally, to prove the effectiveness of the proposed islanding detection strategy, offline digital time-domain simulation studies have been performed on a test microgrid including voltagesourced converter-based renewable/distributed energy resources in MATLAB/Simulink environment for different configurations and load conditions and the results have been verified by comparing with previously reported methods. The results indicate that the proposed method performs fast and precise islanding detection in both low-power and high-power LV microgrids with reasonable impact on power quality according to EN 50160 standard. By combining these fields as active and passive techniques, the proposed hybrid method gives smaller non-detection zones and shorter detection times when compared to frequencyand harmonic-based individual islanding detection methods.