The Economical Solution of Offshore HVDC for Wind Power Integration and Performance Comparison

Abstract:
As offshore wind farm capacity increases and locations extend further into deep seas, High-Voltage Direct Current (HVDC) technology becomes essential for long-distance power transmission. This paper presents three offshore HVDC schemes, including two flexible DC transmission schemes fully based on Modular Multilevel Converter (MMC) valves, as well as an integrated scheme based on diode rectification, then detailing available power semiconductors, sub-module design, and system concepts. By comparing system performance from different aspects, the strengths and weaknesses of each scheme are identified. The results can aid in selecting the optimal design for offshore wind power DC transmission systems, by trade-off the efficiency, reliability, and cost.