Hybrid HVDC connection of large offshore wind farms to the AC grid

The growth of the industry for the integration of offshore wind farms (OWF) has generated great interest in high-voltage DC (HVDC) transmission, especially those based on voltage source converters (VSC). However, line-commutated converters (LCC) are by far the most recognized and widespread HVDC technology. This article investigates the feasibility of a hybrid configuration that combines an LCC with the VSC for the integration of OWF. A hybrid HVDC, with an offshore VSC and onshore LCC, is implemented in PSCAD/EMTDC. The OWF is composed of variable speed wind turbines driving permanent magnet synchronous generators. This paper mainly focuses on the control strategy for overall system. The proposed control strategy is verified through simulation under various conditions, including wind speed variations and onshore faults.