Review of HVDC technologies for weak grid interconnectors

HVDC has experienced substantial growth in utilization globally, attributable to its superior capacity for transmitting large amounts of power relative to its HVAC counterpart and its increasingly competitive pricing. Voltage source converter technology, a variant of HVDC, is particularly well suited for transferring bulk offshore power, whether in point-to-point or multiterminal configurations. Most existing HVDC connections function as interconnections between strong AC grids or between strong and weak/islanded AC grids. However, with the expanding use of distant offshore generation, the establishment of energy islands, and the electrical interconnection of archipelagic nations such as Indonesia, the potential arises for HVDC to link two weak AC grids or even a weak and very weak AC grid. This paper provides a comprehensive review of various HVDC technologies appropriate for such connections, focusing on converters, cables, and circuit breakers. It also offers a technological and methodological assessment of HVDC reinforcement for interconnecting weak AC grids. Furthermore, the paper examines HVDC applications concerning control strategies optimized for weak grid interconnections. Finally, it presents case studies of HVDC implementations for weak grid interconnections in Indonesia.