Performance Analysis of an Islanded Microgrid for Non-Linear and Unbalanced Load

ABSTRACT In a microgrid, voltage source inverters (VSI) are usually used for all kinds of distributed generation interfaces. VSIs play an important role in maintaining the voltage and frequency during islanded mode of operation which is being affected due to unbalanced and non-linear loads. This project report presents design, simulation and analysis of different non-linear loads such as SMPS, CFL etc. and the effect of unbalanced and non-linear loads and there harmonics is being calculated. Further to mitigate such power quality problems conventional proportional integral (PI) and proportional integral plus multi resonant controller based compensation strategy in a single fundamental positive-sequence synchronous reference frame is used. Harmonic contents due to different types of loads and sources has been calculated and compared for the different cases with both control strategies. THD is used as the harmonic index to study the effect of the non-linear loads at the utility. Both the control strategies are demonstrated in detail and validated with simulations.