A method of voltage level selection for offshore wind power VSC-HVDC transmission project

Abstract

Offshore wind power has been widely promoted around the world, owing to its abundance and being environmentally friendly. Voltage source converter based high voltage direct current (VSC-HVDC) transmission technology has been utilized for wind power transmission system because of its advantages. In offshore VSC-HVDC transmission system, the DC voltage level is an important index of power transmission capacity. Based on the steady-state current operating interval of the insulated gate bipolar transistors (IGBT), the value range of DC voltage for offshore VSCHVDC transmission system is given, and the value range of DC voltage is revised according to the IGBT transient current limit. Furthermore, the DC voltage level of offshore VSC-HVDC transmission system is determined according to the current limitation requirements of the DC marine cables. On this basis, a 900MW offshore wind power VSC-HVDC transmission project has been taken as an example, the process to select the DC voltage level of the project case is given. The method of voltage level selection proposed is conducive to improving the operation reliability of the offshore VSC-HVDC transmission system, and plays a positive role in improving the utilization rate of offshore wind power and the power system resilience of the onshore power grid.