Operating Experiences and Insights in Future Applications of Grid Forming Capability of VSC HVDC

Due to drastic and fast changes in power systems characterized by a shift from traditional power plans toward renewables and most often converter-based energy sources, the Grid Forming (GFM) control has become a very important topic from Transmission System Operators (TSO), regulators, developer, academia and Original Equipment Manufacturers (OEMs). The utilization of GFM control in High Voltage DC transmission however is not new and started more than 1 decade ago. The paper describes different control concepts and the related suitability to connected AC grid characteristics, reviewing and summarizing some of the most representative early field applications of GFM control, describing many successful experiences where one of the main objectives, while designing the VSC HVDC has been the enhancement of the AC grid stability and resilience. The paper explores the possibilities, but also the limitations that planners and operators should consider while specifying the control features of a new VDC assets, suggests how to possibly maximize robustness and avoid inconsistencies through a closer cooperation between HVDC link developer and technology providers.