Three-dimensional non-detection zone for assessing anti-islanding detection schemes

The non-detection zone is a concept used to evaluate anti-islanding detection methods. The non-detection zone is defined as the loading condition for which an islanding detection method would fail to operate in a timely manner, and it is represented in terms of the load parameters. This article proposes a new three-dimensional non-detection zone representation for quantifying the effectiveness of frequency drift islanding detection methods. The proposed non-detection zone model is represented in terms of active and reactive power mismatch and load quality factor. Various two-dimensional non-detection zone models proposed in the literature are analyzed to highlight the limitations of each model. The analysis is conducted on three different islanding detection methods, including over-frequency protection/under frequency protection, active frequency drift, and Sandia frequency shift methods. The analytical model of the two dimensional non-detection zone representations is presented, and each model is validated through simulation results. The results show that representing the non-detection zone in a two-dimensional space is not sufficient to accurately determine all non-detectable loading conditions. The proposed three-dimensional non-detection zone representation is capable of modeling all possible loading conditions and provides a better approach for assessing islanding detection methods with resistance-inductance-capacitance loads.