基于距离系数的并网系统稳定性参数灵敏度分析法

Distance coefficient-based parameter sensitivity analysis method for stability of grid-connected system

阻抗分析法在分析参数对稳定性的影响时存在离散化分析的局限,且难以量化对稳定性的影响程度.为此,提出了一种基于等效环路增益的三维伯德图距离系数的灵敏度分析方法,其具有定量、直观地研究新能源并网中参数连续变化对系统稳定性的影响规律的优势.该方法通过提取系统等效环路增益的三维伯德图距离系数,利用控制器参数与距离系数之间的导数运算,得到表征系统控制器参数对于稳定性影响的数值结果,为其影响分析提供清晰直观的量化指标.同时,以变流器并网系统及直驱风场经传统高压直流输电送出系统为案例,介绍了所提方法的具体应用,根据参数灵敏度分析结果对控制器参数进行了优化,以规避振荡风险.最后,基于Simulink仿真平台验证了方法的有效性和可行性.

The impedance analysis method has limitations of discrete analysis in analyzing the influence of parameters on stability,and it is difficult to quantify the degree of influence on stability. Thus,a sensitivity analysis method of three-dimensional(3D) Bode diagram distance coefficient based on equivalent loop gain is proposed,which has the advantages of being able to quantitatively and intuitively study the influence of parameter variation on system stability in renewable energy grid-connected system. By extracting the distance coefficients in the 3D Bode diagram of the equivalent loop gain for system and using the derivative opera⁃ tion between the controller parameters and the distance coefficients,the numerical results of the influence of controller parameters on stability are obtained,so that the clear and intuitive quantitative indicators for impact analysis are provided. Taking the grid-connected converter system and the direct-driven wind farm integration through line-commutated converter based high voltage direct current system as examples,the speci-fic application of the proposed method is introduced. The controller parameters are optimized according to the sensitivity analysis results to avoid the risk of oscillation. Finally,the effectiveness and feasibility of the method are verified based on Simulink simulation platform.