适用于海上风电并网的多端柔性直流系统自适应下垂控制研究

DC voltage adaptive droop control of multi-terminal VSC-HVDC system for offshore wind farms integration

多端柔性直流输电技术适用于大规模海上风电场并网,维持直流电压稳定是多端柔性直流输电系统协调控制的主要任务。传统下垂控制采用固定下垂系数,在复杂工况下灵活性较差,为此提出一种自适应下垂控制策略。通过检测换流站的直流电压偏差和功率裕度,采用模糊逻辑推理调整下垂系数。基于PSCAD/EMTDC仿真研究表明:所提自适应下垂控制策略,在换流站功率裕度允许范围内,能够减小传输功率变化造成的直流电压偏差,提高系统运行特性。

Multi-terminal HVDC transmission technology using voltage source converters is suitable for integrating large off-shore wind farms. DC voltage stability is the main problem for coordinated control of Voltage Source Converter based Multi-Terminal High Voltage Direct Current（VSC-MTDC） transmission system. The fixed droop coefficient of the traditional droop control leads to poor flexibility under severe disturbance. On this basis, this paper proposes an adaptive droop control method. By detecting the DC voltage deviation and the power margin, the fuzzy logic control is intended to adjust droop coefficient adaptively. Simulation results in PSCAD/EMTDC show that the proposed adaptive droop control strategy can reduce DC voltage deviation caused by the transmission power change and improve system operating performance within the allowable power margin range.