APPROACHES FOR POWER GRID MANAGEMENT AND ANCILLARY SERVICES WITH DC-AC MICRO-GRIDS COMPRISING OF PV FARM AND HYBRID ENERGY STORAGE SYSTEM

The emergence of the concept of DC grids comes from the fact that there is an increasing number of power grid components that naturally operate with DC power. The combined trend of DC sources and loads in power grids is an important player in the sudden growth of research interest in DC micro-grids and their interplay with the main power grid. Even though DC grids are easy to implement on a small scale and their own, the connection of DC micro-grid with the AC power grid takes research problems to another level. Innovative approaches, methods, distribution system architectures and control strategies are required to manage and mitigate the problems of involving DC micro-grid in conjunction with conventional power grids. Through this research work, novel, innovative and comprehensive system architectures and control strategies are proposed to mitigate some of the problems of DC micro-grid like DC-AC micro-grid interplay during steady-state and dynamic conditions, tandem operation of DC and AC micro-grids for frequency regulation. The thesis also proposes the concept of a DC ring architecture to emulate a small residential community using a common DC-bus-centric structure. The research work aims to provide a comprehensive DC-AC micro-grid design and control architecture that can provide a platform for testing and validation of steady-state and fault time system performance. The proposed methods in each chapter have been incorporated and validated on standard distribution test systems provided by IEEE like the 13 bus and 123 bus systems and hence their analysis is crucial and could serve as a reference for future design and control of DC micro-grids.