Frequency Estimation by Recursive Least Square in Active Islanding Method for Microgrid

Islanding of Microgrid is important in case of grid disconnection. There are various methods of islanding in which passive islanding methods are easy to implement but have large non detection zone (NDZ). The majority of the islanding methods are tested on single phase PV- grid connected system. Very few methods were studied for the multi DG systems. In this paper, passive and active islanding detection methods (IDM) are presented when measurements are carried out at point of common coupling (PCC) when two DGs are linked in parallel. Additionally a new technique is projected here for islanding in which recursive least square algorithm (RLS) is applied for measuring the frequency of active frequency drift (AFD) current. Further comparative analysis is done for active frequency drifts (AFD) with the new proposed method on multi DG system connected to the grid. A change in the distorted frequency generates the tripping signal, in fast manner as compare to AFD. The simulation results are reported based on MATLAB software. The analysis shows that estimation of frequency for current of AFD with RLS approach is more suitable for islanding.