高压柔性直流换流阀系统的动态电磁特性研究

VSC-HVDC (Voltage-sourced Converter High-voltage Direct Current), based on controllable power electronic valve, is used for interconnecting renewable energy with power system, building DC distribution network in cities, and supplying power to remote region. It features compact equipment arrangement, easy to control and convenient to be assembled into large scale in a modular fashion. Furthermore, VSC-HVDC is one of those key technologies in motivating toward smart grid compatible with distributed resource and renewable energy. This project, focuses on addressing some technological problems, such as in system topology optimization and EMC design in Modular Multilevel Converters (MMC) for direct current transmission, is to extract the circuit parameters of primary equipment for both self- and mutual-coupling, and to model the MMC-based power conversion system by equivalent electrical circuit. Subsequently, the dynamic behavior of MMC-based power conversion system under various transient conditions will be analyzed, and the method of balancing voltage and current among different modular be studied. Taking the time-variant topology of MMC-based converters into account, the electromagnetic disturbance on valve switching will be predicted to obtain the transient disturbance characteristics in time- and frequency-domain,and some indexes will be proposed to evaluate the disturbance level. Hence, this project is a strategic plan in domestic design, manufacture and assembly of MMC-based direct current transmission toward high-voltage and large-power, and in power resource distribution toward optimization to secure coherent and sustained development in China.

柔性直流输电是基于全控型器件的新一代直流输电技术，具有可控性好、便于规模化等优点，是风电等新能源接入、大型城市配电网供电的重要技术手段，也是支撑智能电网建设的关键技术和重要装备之一。本课题针对高压柔性直流换流阀系统，围绕系统结构优化设计、电磁兼容设计等核心技术难题，借助于测量和试验手段，应用电路和电磁场分析与综合方法，开展如下研究：（1）研究基于MMC的高压柔性直流换流阀系统中关键设备和元器件自身及其相互耦合的集总参数和寄生参数的提取方法，以及相应的时域和频域等效电路建模方法；（2）研究各类电磁暂态作用下基于MMC的高压柔性直流换流阀系统的动态电磁特性，结合参数灵敏度分析，提出高压柔性直流换流阀系统的动态电压均衡方法；（3）研究基于MMC的高压柔性直流换流阀系统时变拓扑结构的电磁骚扰预测计算方法，获得电磁骚扰的时域和频域特征，进而对高压柔性直流换流阀系统进行电磁骚扰评价。

柔性直流输电是基于全控型器件的新一代直流输电技术，具有可控性好、便于规模化等优点，是风电等新能源接入、大型城市配电网供电的重要技术手段，也是支撑智能电网建设的关键技术和重要装备之一。本课题针对高压柔性直流换流阀系统，围绕系统结构优化设计、电磁兼容设计等核心技术难题，借助于测量和试验手段，应用电路和电磁场分析与综合方法，开展如下研究：（1）研究基于MMC的高压柔性直流换流阀系统的参数提取与建模方法；（2）研究基于MMC的高压柔性直流换流阀系统的动态电磁特性及其均衡方法；（3）研究基于MMC的高压柔性直流换流阀系统的电磁骚扰特性。针对上述研究内容，取得如下研究成果：（1）柔性直流换流阀子模块宽频建模及瞬态分析；（2）大尺度电气设备阻抗宽频特性测量方法；（3）换流阀系统无源设备及元件集成宽频等效电路模型；（4）变压器宽频机理模型及其寄生电容实验提取方法；（5）柔性直流换流阀塔寄生电容提取方法及其应用；（6）超大规模电平数下模块化多电平换流器快速仿真算法；（7）模块化多电平换流器损耗特性及结温预测；（8）柔性直流换流阀无线电干扰预测及电磁环境实测。本课题研究对于提高我国高压柔性直流换流阀系统的电磁兼容设计水平，实现高电压、大容量柔性直流换流阀系统的自主化设计具有重要的战略意义。