The Role of The HVDC System in A Low Inertia AC Grid for Transient Stability Support: A Review

HVDC can be considered a mature technology and has been installed in several countries for different purposes other than transmitting power. The shift from a conventional and centralized electric power plant to a distributed variable renewable energy (VRE) generator has placed HVDC in a significant role to ensure the stability of the grid. This is not only because HVDC has a larger rating than the VRE generator, but also HVDC can be controlled to mimic the operation of the synchronous generator. In this paper, the role of HVDC in supporting the transient stability of a low inertia AC system is explained. The converter can be operated as the grid following/supporting or grid forming mode, depending on how strong the AC grid is. Furthermore, the challenge of implementing these modes is also identified.