Project: 3000 MW VSC Bipole in Europe
Service: VSC HVDC
Year: 2014 — 2015
TGS performed full-scale technology studies in PSCAD for a one-of-a-kind 3000 MW bipole VSC link, which is planned for a future multi-terminal extension. The project involves full bridge MMC converter technology with overhead DC transmission. TGS explored the capabilities of full bridge converters and identified the technical requirements of the project.
The main challenge in this project was the fact that the DC line was sharing towers with the AC lines in certain sections. This made AC-DC coupling and detecting and clearing of inter-system faults critical. Possibilities of mitigating AC-DC coupling through blocking filters and through control modifications were explored. A special control and protection scheme was developed to detect, identify the faulty section of the line, and clear inter-system faults. New control features were required for the HVDC to be compliant with the Utility’s proposed grid code. Also, a protection scheme was developed to detect an open circuit fault in one of the AC lines connecting the converter to the AC system.