【作者】 张宇；

【导师】 秦文萍；

【作者基本信息】 太原理工大学 ， 电气工程， 2022， 硕士

【摘要】 风力发电是传统能源结构向绿色低碳转型升级的重要途径,然而由于风电机组往往通过变换器柔性并网且控制系统复杂。与同步发电机主导的电力系统相比,大规模风电并网的电力系统具有高阶、非线性、多时间尺度等特点,其稳定性问题也更加复杂。时域仿真是分析电力系统稳定性的重要技术手段。由于开发背景和使用目的不同,不同仿真软件提供的双馈风机模型存在一定差异,而模型差异导致的仿真偏差将对电力系统运行控制与决策的正确性产生重要影响。因此,对不同仿真软件进行模型对比与研究具有重要的工程应用价值与实际意义。本文对PSASP的8型双馈直驱通用模型与DIg SILENT中的双馈风机通用模型进行对比。分析两者在风轮机及控制模型、发电机/变换器及变换器控制模型上的差异,根据模型差异设置相应的仿真场景,通过仿真对比两种软件双馈风机输出特性的不同,进而研究两种软件双馈风机模型的特点与适用性,为风电大规模并网仿真分析提供参考,以便选择合适的仿真分析工具。模型复杂、计算量大、仿真时间长等问题给电力系统稳定性分析带来了困难,而现有降阶与简化模型往往存在适用性不足的问题。因此,提出一种通用的简化建模方法,兼顾模型精度和仿真速度是电力系统稳定性分析面临的重大挑战。本文提出一种适用于动态全过程仿真的双馈风机简化建模方法。根据多时间尺度模型简化原理建立双馈风机各控制的动态模型和准稳态模型;从控制参数入手,提出两级轨迹灵敏度分析方法,研究在动态全过程仿真中主导双馈风机输出特性的关键控制;提出一种模型切换控制策略,根据两级轨迹灵敏度分析结果,通过设置阈值建立可调节的模型切换判据,在动态全过程仿真中分时调用各控制的动态模型和准稳态模型,在保证模型精度的同时实现模型的降阶和简化。大规模风电接入给电力系统暂态稳定性带来了很大的冲击,现有文献对暂态稳定性影响因素的分析并没有统一的结论。本文将风电大规模接入的电力系统等值为扩展双机系统,推导风机接入前后同步发电机的功角摇摆方程,分析同步发电机功角摇摆方向的变化,根据功角摇摆方向变化设计仿真场景,分别对风机接入位置、同步发电机出力变化、风电接入比例三种因素进行仿真,对风电接入对暂态稳定性的影响进行研究与分析。更多还原

【Abstract】 Wind power generation is an important way to transform and upgrade the traditional energy structure to green and low-carbon.However,wind turbines are often connected to the grid flexibly through converters and the control system is complex.Compared with the power system dominated by synchronous generators,the large-scale wind power grid-connected power system has the characteristics of high order,nonlinearity and multiple time scales,and its stability problem is also more complicated..Time domain simulation is an important technical means to analyze the stability of power system.Due to different development backgrounds and usage purposes,there are certain differences in the DFIG(Doubly Fed Induction Generator)models provided by different simulation software,and the simulation deviation caused by the model differences will have an important impact on the correctness of power system operation control and decision-making.Therefore,the model comparison and research of different simulation software has important engineering application value and practical significance.This paper compares the general model of PSASP’s 8-type DFIG with the general model of DFIG in DIg SILENT.Analyze the differences between the two in wind turbine and control model,generator/converter and converter control model.Set the corresponding simulation scene according to the model difference.By comparing the output characteristics of the DFIG in the two softwares,the characteristics and applicability of the DFIG models of the two softwares are studied,which can provide a reference for the large-scale grid-connected simulation analysis of wind power,so as to select appropriate simulation analysis tools..The complexity of the model,the large amount of calculation,and the long simulation time bring difficulties to the analysis of power system stability,and the existing simplified models often have the problem of insufficient applicability.Therefore,it is a major challenge for power system stability analysis to propose a general simplified modeling method that takes into account model accuracy and simulation speed.In this paper,a simplified modeling method of DFIG suitable for dynamic whole process simulation is proposed.According to the multi-time scale model simplification principle,the dynamic model and quasi-steady-state model of each control of the DFIG are established.Starting from the control parameters,a two-level trajectory sensitivity analysis method is proposed to study the key control that dominates the output characteristics of the DFIG in the dynamic whole process simulation.A model switching control strategy is proposed.According to the two-level trajectory sensitivity analysis results,an adjustable model switching criterion is established by setting the threshold,and the dynamic model and quasi-steady-state model of each control are called in time-sharing in the dynamic whole process simulation.The model can be reduced and simplified while ensuring the accuracy of the model.The continuous improvement of wind power penetration has greatly impacted the transient stability of the power system.There is no unified conclusion on the analysis of the influencing factors of transient stability in the existing literature.In this paper,the power system connected to large-scale wind power is equivalent to a dual-machine system.The power angle swing equation of the synchronous generator before and after the fan is connected is derived,and the change of the power angle swing direction of the synchronous generator is analyzed.The simulation scene is designed according to the change of the swing direction of the power angle.Three factors are simulated respectively,including the location of the wind turbine,the output change of the synchronous generator,and the proportion of the wind power connection,and the influence of the wind power connection on the transient stability is studied and analyzed.更多还原