Emergence of Advanced Multi-Terminal HVDC Transmission Systems and DC Grids

The transfer of bulk electrical power over long distances can be done by high voltage alternating current (HV AC) transmission systems. These HV AC power transmission systems have their perfections and imperfections. To enhance the existing power transmission systems, high voltage direct current (HVDC) power transmission systems are a sustainable solution. The emergence of advanced HVDC systems is so rapid that they are replacing their counterpart HV AC systems in many parts of the world. In this paper, the prominence of modern HVDC power transmission systems is highlighted. The topologies, converter assortments, contrasts, and modeling methods are discussed. The renewable energy sources (RES) including solar photovoltaic (PV) parks and mainland/ onshore/ offshore wind farms can be assimilated into the existing AC grids via advanced HVDC converters. The perceptions of multi-terminal HVDC systems and DC grids are presented, whereas, the challenges concomitant with the future DC grids are also emphasized.