Islanding event detection technique based on change in apparent power in microgrid environment

Malfunctioning of islanding detection algorithms leads to system instability, failure of reclosing, and damage to load-side equipment. It also threatens security personnel. Therefore, islanding detection is an essential task for the proper functioning of the distribution system. In this paper, an islanding detection technique is presented for a grid-connected distributed power generation system. The proposed islanding detection technique is based on the change in superimposed positive sequence apparent power (CSPSAP). The CSPSAP-based islanding detection technique discriminates islanding and non-islanding events. The accessibility of positive sequence components makes the technique suitable for islanding detection for a wide range of active and reactive power mismatches. It works effectively in zero power mismatch conditions. The effectiveness of the proposed technique is verified for islanding events in cases of distributed generation disconnection with the inclusion of noise, various irradiances, and unbalanced load. Even the proposed technique proves its efficacy under various non-islanding events such as capacitor switching, different fault cases, and load switching. The impact of the proposed technique is also validated in cases of islanding and non-islanding under weak grid systems. The proposed islanding detection technique is fast due to the utilization of local measured parameters at the point of common coupling and does not have power quality degradation issues. Effects of the false detection zone and non-detection zone are also discussed with regard to the proposed technique. The proposed technique is also validated on the real-time platform of the OPAL-RT. MATLAB 2018a software is considered to model and simulate a microgrid.