含风电场电网的概率电压稳定性研究

发布时间：2018-01-18 04:00

本文关键词：含风电场电网的概率电压稳定性研究　出处：《上海电力学院》2014年硕士论文　论文类型：学位论文

【摘要】：随着风力发电技术的不断进步，风电场在系统中的比例不断增加，风电对电网电压稳定性的影响也越来越明显。由于风能的间歇性、随机性等特点，电力系统处于不断变化的运行方式下，此时传统的确定性分析方法已经无法全面描述系统的电压稳定性。因此，本文采用概率法评估风电并网对系统的电压稳定性的影响是十分有意义的。含风电场电力系统的概率潮流计算是概率电压稳定性研究的基础，考虑了节点功率变化的系统多运行方式，通过一次计算可以得到系统潮流的概率分布。在IEEE3机9节点系统上，本文用双馈风电机组组成的等值风电场替代某输出功率相同的同步发电机组，采用半不变量法进行了概率潮流计算，并将潮流计算结果与蒙特卡罗模拟法计算结果进行了比较分析。本文采用小干扰分析法研究含风电场电压稳定性，应用PMT建模技术建立了适用于电力系统小干扰稳定分析的电力系统网络、负荷、同步发电机组和DFIG风电机组完整模型，简化了电力网络的状态矩阵的形成过程。特别是双馈感应风力发电机组部分，详细推导和建立了其适用于小干扰稳定分析的机电暂态线性化模型，包括感应发电机模型、交直交变频器模型、轴系模型、桨距角控制模型，以及其他文献较少涉及的最大风能跟踪的风功率模型和完整的变频器控制系统模型。在小干扰稳定分析基础上，采用概率法求出系统状态矩阵所对应的特征根的概率分布，找出系统的概率失稳模式。本文提出电压稳定相关比，作为失稳模式下区分电压失稳和功角失稳的判据，将概率特征根分析法拓展到电压稳定性研究中。通过电压失稳模式系数找到电力系统电压薄弱点，并在电压薄弱点增设鲁棒的SVC改善系统的电压稳定性。最后，分别在IEEE3机9节点系统和八机系统上进行了仿真分析，结果表明风电场的接入增加了电力系统小干扰电压失稳的概率，，增设SVC可以在一定程度上改善系统的电压稳定性。
[Abstract]:With the development of wind power generation technology, the proportion of wind farm in the system is increasing, and the influence of wind power on the voltage stability of power grid is becoming more and more obvious. Under the changing operation mode of power system, the traditional deterministic analysis method can not fully describe the voltage stability of the system. In this paper, the probabilistic method is used to evaluate the influence of wind power grid connection on the voltage stability of the system. Probabilistic power flow calculation with wind farm power system is the basis of probabilistic voltage stability research. The probabilistic distribution of the system power flow can be obtained by one calculation. In the 9-bus system of IEEE3 generator, the equivalent wind farm composed of doubly-fed wind turbines is used to replace a synchronous generator set with the same output power. The semi-invariant method is used to calculate the probabilistic power flow, and the results of power flow calculation are compared with the results of Monte Carlo simulation. In this paper, the small disturbance analysis method is used to study the voltage stability of wind farm, and the PMT modeling technology is used to establish the power system network and load suitable for the small disturbance stability analysis of power system. The complete model of synchronous generator and DFIG wind turbine simplifies the forming process of state matrix of power network, especially the part of doubly-fed induction wind turbine. The electromechanical transient linearization model, including induction generator model, AC-DC converter model, shafting model and pitch angle control model, is derived and established in detail. And the wind power model of maximum wind tracking and the complete control system model of frequency converter are seldom mentioned in other literatures. On the basis of the small disturbance stability analysis, the probability distribution of the characteristic root corresponding to the state matrix of the system is obtained by using the probability method, and the probabilistic instability mode of the system is found. In this paper, the voltage stability correlation ratio is proposed. As a criterion to distinguish the voltage instability from the power angle instability in the unstable mode, the probabilistic eigenvalue analysis method is extended to the study of voltage stability. The voltage weakness of the power system is found by the voltage instability mode coefficient. A robust SVC is added to the voltage weakness to improve the voltage stability of the system. Finally, the simulation analysis is carried out on IEEE3 9-bus system and eight-bus system respectively. The results show that the access of wind farm increases the probability of small disturbance voltage instability in power system. The addition of SVC can improve the voltage stability of the system to some extent.
【学位授予单位】：上海电力学院
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM712

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