Dynamics and Control of Electric Transmission and Microgrids

12Microgrids: Operation and Control

12.1 Introduction

The penetration of distributed generation (DG) at medium and low voltages in electrical distribution systems has been increasing over the years, particularly in developed countries. The distributed generation encompasses a wide range of prime mover technologies, such as internal combustion (IC) engines, gas turbines, microturbines, photovoltaic (PV), fuel cells, and wind turbines (WT). Most emerging technologies require an inverter to interface with the distribution systems [1]. These technologies, collectively labelled “distributed energy resources” (DERs) can substantially reduce carbon emissions, thereby reducing greenhouse gas emissions (as mandated by the Kyoto Protocol) [2]. Another objective is to increase the contribution of the renewable energy component (wind, solar, and hydro), which will overcome the problems of dwindling energy sources based on coal and gas. The presence of distributed generation close to the loads can enhance power quality and reliability (PQR). The occurrence of major power blackouts in 2003 in North America and Europe has also contributed to the desire of customers to install local distributed generation which can minimize the impact of power blackouts. The application of combined heat and power (CHP) equipment, where required, results in increased energy efficiency. These are the major benefits of DER that have resulted in the new paradigm of developing active distribution networks in contrast ...