Multifunctional capabilities of converter interfaced distributed resource in grid connected mode

Renewable energy sources like wind, solar and hydro are reliable alternatives to the conventional energy sources such as oil, natural gas, or coal. Distributed power generation systems based on renewable energy sources have gained tremendous importance worldwide and the trend is catching up in India as well. These are currently being interfaced to the existing systems using voltage source converters (VSC's). The control of such distributed resources is significantly different than the conventional power systems mainly because the VSC's have no inertia unlike the synchronous generators. As the percentage of renewable sources integrated into the utility grid increases, it becomes necessary to adhere to new and strict power quality guidelines. Most of these standards are developed for proper running of these resources in grid and islanded modes and also ensure power quality standards are met. This paper considers the multifunctional capabilities of distributed resource connected to the grid via a voltage source inverter. A simple control algorithm is developed for real and reactive power sharing of the load between various sources. This control algorithm is modified for power quality improvement. A voltage source inverter (VSI) based distributed energy resource is connected to three phase utility grid feeding a variety of linear loads. Simulation results are discussed for the model developed using Sim-Power systems of the Matlab software. The control algorithm can be extended for several distributed resources connected in parallel with suitable modifications.