海上风电场并网柔直系统的故障穿越协调控制策略

摘要

分析了基于H桥换流单元与集中式斩波电阻的多电平集中式卸荷电路（ dynamic braking resistor ，DBR），介绍了其结构拓扑、参数设计与控制方法，并对比模块化多电平卸荷电路，验证其故障穿越（ fault ride －through，FRT）性能。针对海上风电场并网柔性直流输电系统，结合双馈与永磁直驱风场侧换流站的交流电压降压法，利用风电机组（ wind turbine generator ， WTG）自身功率调节能力，设计FRT协调控制策略，在保证系统故障穿越性能的前提下，缩减卸荷电路所需容量，适用于高压大容量场合。依据德国已投运Borwin1工程的参数，在PSCAD／EMTDC电磁暂态仿真软件中搭建三端柔性直流输电系统模型，验证了所提协调控制策略具有良好的FRT控制效果。%This paper analyzes multilevel lumped DBR circuits which are based on the H-bridge inverter unit and sim-ple lumped air-cooled resistors , introducing their structural topology , parameter design and control method , and dem-onstrates the FRT performance of multilevel lumped DBR circuits by comparing with the modular multi -level DBR cir-cuits.For the offshore wind farm connected by flexible HVDC transmission system , combining the AC-voltage magni-tude reduction method of double-fed and permanent magnet direct-driven wind farm converter station , the FRT coordi-nation control strategy is designed by using WTGs ’ ability of power regulation of wind farms .Under the premise of en-suring FRT performance of system , the study reduces required capacity of DBR circuits , thus to adapt for large-capac-ity and high-voltage situations.Based on parameters of German Borwin1 project, a flexible three-terminal HVDC sys-tem model is established in PSCAD/EMTDC software and simulation results show that the coordination control strategy has good FRT control effect .