为将大规模风力发电输送到数干km以外的负荷中心,提出一种将风电场和常规电厂捆绑并网的三端直流输电系统,设计了全系统以及各个换流站的控制器。全系统静态伏安特性的分析结果表明该系统具有较强的静态稳定性。利用PscAD/EMTDc建立该系统的详细模型,仿真验证了该系统在启动、稳态运行、风电功率波动及故障工况下的运行特性。研究结果表明,该系统在技术上是可行的。该系统为大规模风电的远距离传输提供了一种新的选择。
A three-terminal HVDC system was proposed to transmit bulk inland wind power over thousands of kilometers. Wind power fluctuation was compensated by the conventional power plants to provide highly controllable electric power to the load centers. Control strategies for the individual converter and the whole system were designed. Analysis of the voltage-current characteristic of the system indicated that the proposed system was always stable in steady state. Simulations using PSCAD/EMTDC verified the successful operation during starting, steady state, wind power variations and faults. The proposed scheme is technically feasible. The proposed scheme provides a novel alternative network transmission scheme to the conventional point-to-point HVDC scheme.