Analysis on the construction scheme of the booster station of the offshore wind power HVDC grid-connected system

Compared with the decreasing onshore wind energy resources, offshore wind power resources have richer reserves and broader development prospects, which has attracted worldwide attention. Offshore wind power has significant advantages such as high wind speed, high power and stable operation. Its energy efficiency is 20% ~ 40% higher than that of onshore wind farm, which is very suitable for large-scale development. In recent years, the installed scale of offshore wind power in China has increased rapidly. The development of offshore wind power does not occupy coastline and waterway resources and avoid adverse impact on coastal industrial production and residents' life. It is a "potential stock" for future wind power development. Compared with the existing technology, the offshore wind power DC acquisition and boost system based on full DC conversion adopts DC transmission technology from wind power acquisition to transmission, which solves many technical problems caused by AC cable acquisition. While taking into account the advantages of offshore wind power long-distance DC transmission technology, this scheme has become a new development direction of offshore wind power grid connection technology. Therefore, it is urgent to analyze the requirements of voltage level, transmission and distribution, fault isolation and transformation at each input of DC booster station. On this basis, the overall cost, operation efficiency and reliability of the booster station are comprehensively considered. An integrated scheme of DC booster station with voltage conversion, power flow distribution and fault protection is proposed. The integration scheme includes the integration of main circuit design, converter topology and control and protection strategy, which will effectively improve the operation reliability of offshore wind power DC boost system. This paper focuses on the design requirements and research of the core equipment of the booster station of the offshore wind power DC pool booster system. The purpose is to promote the development and engineering of this new wind power grid connection technology and provide an efficient grid connection solution for the large-scale development of offshore wind power.