Electric Power ›› 2022, Vol. 55 ›› Issue (6): 118-127.DOI: 10.11930/j.issn.1004-9649.202108068

• Power System • Previous Articles     Next Articles

A Feasible Topology of DC Collection Valve for Long-Distance Offshore Wind Farms and Cost-Effective Analysis

LIAO Xiupu1, ZHOU Quan1, LI Lei2, LI Binbin2, WANG Zhiyuan2, YANG Ming2, XU Dianguo2   

  1. 1. Maintenance and Test Center of EHV Power Transmission Company, CSG, Guangzhou 510663, China;
    2. Department of Electrical Engineering and Automation, Harbin Institute of Technology, Harbin 150001, China
  • Received:2021-08-18 Revised:2021-11-07 Online:2022-06-28 Published:2022-06-18
  • Supported by:
    This work is supported by National Natural Science Foundation of China (Energy-Storage Principle Based High-Voltage Large-Power DC/DC Converter Topology and Its Control, No.51807033) , and Key Laboratory of EHV Foundation (No.012000KK58210009).

Abstract: HVDC is a preferred technology for high-power and long-distance offshore wind farms, and the valve plays a pivotal role. Due to the high cost, large footprint and weight of valve, and high construction cost of offshore platform, an evolution is anticipated from traditional modular multilevel converter (MMC) based AC collection valve to the DC/DC transformer (DCT) based DC collection valve. Firstly, based on analyzing the technical characteristics and feasible topology of the DC collection valve, it is proposed to adopt the capacitive energy transmission (CET) principle based DCT, which presents low-cost, small footprint, light weight and low power loss. And then the topology of CET-DCT is improved into the bipolar topology for engineering applications, and the operation principle is also discussed. The effectiveness of the DC collection valve has been verified by simulation and experimental results, and the cost-effectiveness of the CET-DCT based DC valve is concluded by comparison with the MMC based AC collection valve.

Key words: offshore wind farm, high-voltage direct-current (HVDC), DC/DC converter, MMC, valve