ABSTRACT
The microgrid concepts emerged as one way to handle and operate the growing number of distributed generation units, used in power systems. Microgrids are envisioned as smart grid building blocks, having the potential for improved resiliency, higher energy efficiency, service quality, supply security and integration of renewable energy resources. At the same time, increased complexity of integrating distributed energy resources presents several protection and control challenges that can be solved by microgrids. Microgrids are state-of-the-art electric networks consisting of distributed generators, energy storage units, uncontrollable, controllable and sensitive loads, being a major smart grid application, having the capability to operate grid-connected or in intentional or unintentional islanded mode, with the objective to ensure improved reliability, supply security, service quality and efficiency. Microgrid operation goal is to provide reliable and high-quality power to loads regardless of the grid conditions. Microgrids, operating as small controllable power subsystems, have characteristics and capabilities such as better service quality, faster service restoration, resilience, reliability, supply security and grid operational optimality. Microgrids can be easy operated grid interconnected or islanded, depending on factors like planned disconnections, outages, extreme events or economical convenience. Due to the needs to capitalize benefits of distributed generation, the concept has gained significant interests as effective local power system solutions.
