MMC-HVDC系统主设备参数的非线性规划设计方法

模块化多电平换流器(MMC)已成为柔性直流输电系统的主流拓扑结构,其主设备参数的设计对系统的投资和运行性能具有决定性作用。基于模块化多电平换流器的高压直流输电(MMCHVDC)系统关键主设备参数包括联接变压器二次侧额定电压、变压器漏抗、桥臂电抗、子模块电容等,单个主设备参数的独立设计忽略了不同设备多个参数之间的耦合特性。文中构建了不同设备多个参数设计的约束方程组和目标函数,并提出了基于非线性规划法对MMC-HVDC系统主设备参数设计的整体算法,该整体算法综合考虑多个参数和不同设备设计原则之间的耦合特性,从而达到可靠的优化设计结果。最后针对某MMC-HVDC系统工程进行了参数优化设计,基于PSCAD/EMTDC的计算和仿真结果基本吻合,验证了所提算法的有效性。

Nonlinear Programming Design Method of Main Equipment Parameter for MMC-HVDC System

The modular multilevel converter(MMC)is being widely-used as the main topology of the voltage source converter based high voltage direct current transmission(VSC-HVDC)projects. The design of the main equipment parameters is of decisive significance, which is related to the investment and operation performance of the system. The main equipment parameters include the rated valve side no-load voltage of the coupling transformer, the leakage reactance of the coupling transformer, the arm inductance and the sub-module capacitance. Independent design of a single parameter leads to the neglect of the coupling characteristics between multiple parameters of different equipment. In this paper, the objective function and constraint equations are designed with an eye to multiple parameters of different equipment. And a nonlinear programming method is proposed to calculate these parameters. The nonlinear programming method takes into consideration the coupling characteristics between multiple parameters of different equipment. The integral algorithm proposed is implemented in the design of a MMC-HVDC project. Time-domain simulation studies based on PSCAD/EMTDC are performed to show that the calculation and simulation results with the method are basically consistent. This work is supported by National Natural Science Foundation of China(No. 51507060)and Fundamental Research Funds for the Central Universities(No. 2016MS07).