A Mathematical Formulation for Assessment of Power Quality in Microgrid

The electricity sector in India had an installed capacity of 233.929 GW as of December 2013. India currently suffers from a major shortage of electricity generation capacity, even though it is the world's fourth largest energy consumer after United States, China and Russia. The utilization of renewable energy sources such as solar power, wind power, biomass power etc. play a dominant role in electricity generation, with the increase in the global warming during recent years. Several advantages such as environmental friendliness, expandability, flexibility and controllability have made various renewable and nonconventional micro sources, an attractive option for configuring modern electrical grids. A microgrid consists of cluster of loads and distributed generators with their energy storage equipments. It operates as a single controllable system for the whole system. As an integrated energy delivery system microgrid can operate in parallel with or isolated from the main power grid. The microgrid can be designed to meet the special requirements such as enhancement of local reliability, increased efficiency and stability. In this paper, a new mathematical formulation is presented, which facilitates the analysis of power quality of the energy storage system of a microgrid to which “n” number of units are connected. The new formulation reduces the complexity in analyzing the power quality of various units. This paper will help the power system planners to know at which point of time the particular unit does not show the effective operation and several essential steps can be taken to improve the power quality of the system, when the microgrid energy storage system is in operation. The practical results show that this formulation is true and applicable for all reserve capacities of microgrid with “n” units in operation. Keywords— Renewable Energy Sources, Microgrid (Intelligent Grid), Inverter, Energy Storage Unit, AC Loads.