Caprivi Link HVDC Interconnector: Comparison between energized system testing and real-time simulator testing

SUMMARY The Caprivi Link HVDC Scheme in Namibia, connects the ac networks of Namibia and Zambia with 950km of overhead line operating at -350kV dc. The 300MW monopole phase of the scheme was set into commercial operation in October 2010. The scheme has been planned for a future bipole extension to 600MW. The scheme utilises Voltage Sourced Converters (VSC) and is the first scheme to use VSC technology with overhead lines. The scheme connects two presently very weak ac networks where the fault levels are in the order of the rated power of the converters. This presented unique challenges in the studies and design phase of the scheme. As a final verification of the system studies and control and protection system performance, factory system testing and energized system testing were performed. The factory system test was performed with the complete control and protection software and hardware together with a real-time simulator with reduced ac network models which included machine dynamics. An extensive energized system testing program was performed during commissioning. Some important tests from the factory and field are presented, compared and discussed. The results of the energized system testing were in line with the factory system testing.