Distributed Generator Based DVR Application to a LV Distribution Grid

In this work, small distributed power generators of renewable energy sources are connected to the distribution grid with nonlinear/dynamic loads. The effect on the power quality of the proposed system is analyzed via dynamic voltage restorer (DVR). The distributed generators (DGs) are integrated and fed to distribution grid through de link of DVR interfacing inverter which is a series inverter linking the DGs to the distribution grid. The DGs as energy storage device regulates the dc link voltage of DVR. The distributed generator consisting of a photovoltaic system (PVS), a wind energy conversion system (WECS) and a micro hydro system (MHS) is proposed. The motivation is on improvement of power quality (PQ) in terms of harmonics and voltage sag. An instantaneous symmetrical component theory (ISCT) for fundamental voltage extraction and hysteresis current control technique for PWM generation is implemented. The complete system is modeled using MATLAB/Simulink SimPower system block set. The proposed system is subjected to nonlinear and dynamic loads and the simulated results are presented. The total harmonic distortion (THD) is shown to analyze the harmonic content in load voltage. The performances of the DVR are found to be tolerant under various load perturbations.