Power Quality Issues in Microgrid

Modern society is highly dependent on electrical energy for its sustainable development. Conventionally, electricity is generated primarily through thermal power stations, hydro power stations and nuclear power stations etc. Hydro power plants use water as a source which is renewable, green (non-Polluting) and available free of cost. But commencement of large hydro large hydro power plants has certain key concerns such as large capital requirement, longer commissioning time periods, damage to ecology and environment and huge displacement of population living around. Nuclear power plants require nuclear fuel. Until operating under safe conditions do not pose any threat but there always have been serious concerns regarding safe disposal of radioactive waste, and to control radioactive exposure under accidents if any. Thermal power plants generate electricity by burning of fossil fuels (coal, gas, oil). Burning of fossil fuels has serious concerns of environment degradation on account emission of gasses. Resources of fossil fuels are limited, hence depleting at fast rate.

In nutshell, it can be envisaged that, demerits of conventional generation have started outweighing their merits. To reduce dependency on conventional resources nature has bestowed the planet with renewable energy resources such as, solar energy, wind energy, geothermal energy, tidal energy, biomass etc. These resources are available in abundance and that even at free of cost. Recent advancement in the field of renewable energy technologies has made it possible to harness the renewable resources on large scale and alleviate the stress on conventional generation.

As per United States, Department of Energy a microgrid is defined as: "Microgrids are localized grids that can disconnect from the traditional grid to operate autonomously. Because they are able to operate while the main grid is down, microgrids can strengthen grid resilience and help mitigate grid disturbances as well as function as a grid resource for faster system response and recovery".

The Consortium for Electric Reliability Technology Solutions, CERTS, has published a 'White Book' to do a detailed exposition of microgrid [2]. CERTS defines microgrid as "an aggregation of loads and micro-source providing both power and heat." As per the various definitions of the microgrid, a microgrid is presumed to be a group of interconnected distributed energy resources and loads with precisely defined boundaries of electrical system.