DSRF and SOGI based PLL-two viable scheme for grid synchronization of DG systems during grid abnormalities

Distributed Generation (DG) System based on renewable energy sources provides a good substitute to the centralized power generation systems which consumes fossil fuels and has imposed several problems on the environment. The safe operation of DG systems requires proper synchronization with power grids by using power electronics converters. The use of Phase Locked Loop (PLL) is an important technique for grid synchronization along with control optimization. This paper presents a comparative study between Dual Synchronous Reference Frame (DSRF) PLL based on synthesis circuit and Second Order Generalized Integrator (SOGI) based PLL. The comparative study has been made on the basis of how they track the phase angle during different abnormal grid conditions like voltage sag, line to ground fault and frequency deviations. The results are obtained from MATLAB/SIMULINK environment and are analyzed for feasibility of the study.