HVDC Connection of Offshore Wind Parks: VSC vs LCC with STATCOM

It is now clear that the installation of offshore wind parks is the next step towards an even more widespread use of wind power. In what concerns the interconnection of remote offshore wind parks to the existing onshore grid, for distances over 50 km and/or installed capacities above 100 MW, High Voltage Direct Current (HVDC) technology seems to be more adequate than High Voltage Alternating Current (HVAC). This paper addresses only the interconnection of offshore systems with the onshore grid through the HVDC technology. Two HVDC technologies are compared: HVDC using Line Commutated Converters (HVDC-LCC) and HVDC using Voltage Source Converters (HVDC-VSC). As it is known that LCC technology is unable to offer reactive power support in fault conditions, the association with a STATCOM is considered. Specific studies are performed in both steady-state and transient conditions of the grid in order to evaluate the pros and cons of each HVDC technology. The impact of the HVDC technologies in the compliance of existing grid code requirements is also assessed.