中文摘要：

为提高柔性直流输电系统（VSC-HVDC）的暂态稳定性,建立基于同步坐标的暂态数学模型,设计了基于正常及故障工况的控制系统.针对VSC-HVDC的高阶阻频特性建立内外环控制器,并基于频域稳定分析法得出内环控制参数的设计方法,同时分析了对称短路故障时的系统响应,建立了基于两站通信的故障切换策略以及涉及从内外环控制器至阀控层的协调越限控制策略.基于PSCAD/EMTDC对VSC-HVDC系统进行仿真分析,仿真结果验证了正常和故障运行时控制策略的有效性,以及控制参数设计方法的合理性.

英文摘要：

For improving transient stability of VSC-HVDC （voltage source converter based high voltage direct current transmission）, a mathematical model is established in synchronous frame and a control system is designed in normal and fault situations. Based on high-order impedance-frequency characteristic of VSC-HVDC, inner and outer con- trollers are established, and parameter design method of inner controller is obtained based on frequency domain stabil- ity analysis. Response is analyzed in symmetrical short circuit situation, and a fault switching strategy based on two- station communication and a coordinate trans-limits control strategy concerning inner and outer controllers and valve controller are established. VSC-HVDC is simulated in PSCAD/EMTDC, and rationality of parameters design method and validities of control strategies are verified by simulation results.