中文摘要：

混合直流输电系统结合了传统电网换相换流器(LCC)和电压源换流器(VSC)的优点,具有广泛的应用前景。文中针对整流侧为LCC换流站、逆变侧为VSC换流站的混合直流输电系统,介绍了单极型、伪双极型、双极型3种不同混合直流结构的特点及应用场合。考虑到混合直流输电系统的主电路参数和控制系统参数对系统的运行特性都有直接的影响,提出了一种可以同步优化主电路和控制系统参数的方法。首先,重点阐述了系统参数中直流平波电抗器L和直流电容器C的参数设计原则,然后基于Simplex算法对LC参数以及两侧控制器比例-积分的参数进行了优化。在电磁暂态仿真软件PSCAD/EMTDC下搭建了混合直流输电系统的模型,仿真结果表明,使用Simplex算法对系统参数进行优化后,其运行特性将得到改善,从而验证了所提出的参数设计优化方法的有效性。

英文摘要：

By combining the advantages of line commutated converter (LCC) and voltage source converter (VSC),the hybrid high voltage direct current (HVDC) transmission system has extensive application prospects.Based on the hybrid HVDC transmission system,whose rectifier is LCC and inverter is VSC,the characteristics and application fields of monopole, pseudo-bipole and bipole hybrid structures are described.In consideration of the main circuit system parameters and control parameters having direct influence on the system operation performance,a novel method of synchronously optimizing the main circuit system parameters and control parameters is proposed.Firstly,the parameters design principle of smooth reactor L and capacitor C at direct current side is presented,then the LC parameters and proportional-integral control parameters are optimized based on the Simplex algorithm.A hybrid HVDC transmission model is developed in PSCAD/EMTDC,the simulation results showing that its operation performance is improved with optimized parameters,proof of the effectiveness of the proposed optimized method. This work is supported by National Natural Science Foundation of China (No.5 1 1 77042) and Specialized Research Fund for the Doctoral Program of Higher Education(SRFDP) of China(No.20130036120006).