适用于VSC-HVDC系统的静态电压稳定分析改进方法

An improved static voltage stability analysis method for VSC-HVDC system

含电压源换流器的高压直流输电(voltage source converter-high voltage direct current,VSC-HVDC)技术是近年来的研究热点,而对于VSC-HVDC系统的静态电压稳定分析方法的研究却很少。泰勒级数法在处理纯交流系统的静态电压稳定分析时具有计算速度快的优点,本文基于泰勒级数提出了一种适用于VSC-HVDC系统的静态电压稳定分析改进方法。首先建立了VSC-HVDC系统的电压稳定分析数学模型,由于系统功率参数是节点电压幅值的可导反函数,将负荷节点功率在靠近极限潮流点处展开为关于节点电压幅值的泰勒级数,最后由泰勒级数快速精确地求取电压稳定鞍结分岔点。通过与连续潮流法的结合和泰勒级数展开点的选择,解决了在纯交流系统中泰勒级数法的缺陷,提高了计算精度。

VSC-HVDC(voltage source converter-high voltage direct current)system is a research hotspot in recent years.However,the static voltage stability analysis methods for VSC-HVDC system are few.The Taylor series method has the advantages of fast calculation for static voltage stability analysis of pure AC system.Therefore,this paper presents a static voltage stability analysis method for VSC-HVDC system based on the Taylor series.Firstly,this paper establishes the mathematical model of static voltage stability analysis.Because the system power parameter is the inverse function of the node voltage amplitude,the load node power can be expanded to the Taylor series of the node voltage near the limit current point.According to the characteristics of the Taylor analytic polynomial,the saddle node bifurcation point of voltage stability of the VSC-HVDC system can be quickly and accurately calculated.In this paper,the defects of Taylor series method in pure AC system are solved and the accuracy is improved by combining with the continuation power flow method and selecting the Taylor series expansion point.