【作者】 李季；

【导师】 周雪松；

【作者基本信息】 天津大学 ， 电力系统及其自动化， 2013， 博士

【摘要】 风力发电是目前发展最成熟的新能源发电方式，发展风力发电不仅可以优化国家的能源结构、改善不断恶化的环境，而且有利于促进电力系统经济稳定运行。随着风电产业的迅猛发展以及风电场规模化建设成效显著，风电并网对电力系统稳定性尤其是对电压稳定性的影响愈显突出。风电系统是一个强非线性动态系统，分岔理论是研究非线性动态系统结构稳定性的有力工具。为此，本文基于分岔理论研究含风电场的电力系统的电压稳定性，深入研究与电压失稳密切相关的分岔形式。具体包括以下几个方面的工作：（1）推导了普通异步发电机的动态方程及静态方程，建立了实用化的基于普通异步发电机的风电机组的总体数学模型，分析了风电场的风速波动对于异步发电机的有功-无功运行特性的影响，以及风电机组输出功率变化对系统电压稳定性的影响规律，得到风电场对接入地区电网的电压稳定性的影响机理。研究表明，风电场电压稳定性降低主要由于风电场吸收大量无功功率，导致电网向风电场输送的无功功率增加，造成线路的电压降落较大所致。（2）提出了应用多参数延拓追踪算法计算多维分岔边界或超曲面，研究了风电场有功出力波动以及静止无功补偿器对含风电场的电力系统的电压稳定性的影响，得到了风电场的注入有功功率、静止无功补偿器控制参数和励磁系统参数对鞍结分岔的影响。提出了应用二次多项式的非线性解析表达方法，解析描述参数空间的鞍结分岔边界或超曲面，通过仿真验证了该方法的准确性和有效性。（3）通过分析风电场功率参数、静止无功补偿器参数等对Hopf分岔点的影响，得到了风电场注入功率与含风电场的电力系统的电压失稳的关系。从结构稳定性的角度分析了静止无功补偿器对系统特征多项式的控制作用，得到了静止无功补偿器对动态电压稳定性的改善机理。研究表明，静止无功补偿器通过调整系统局部结构参量，提高母线电压的抗扰能力，强化系统平衡点的稳定性，延迟Hopf分岔，进而提高非线性电力系统的动态电压稳定性。（4）提出了采用静止无功补偿器等动态无功补偿装置与线性反馈控制方法相结合的Hopf分岔的控制方案，设计了常规电力系统及含风电场的电力系统的线性反馈Hopf分岔控制器，通过仿真验证了该Hopf分岔控制器能够有效控制Hopf分岔，进而改善系统的动态电压稳定性。基于异步发电机的风电场参数和静止无功补偿器参数的多参数分岔分析更好地揭示了含风电场的电力系统电压稳定性的分岔机理，同时对于提高电压稳定性的分岔控制研究具有重要的理论意义和应用价值。更多还原

【Abstract】 The wind power is the most developed ways of generating electric power withnew energy resources. The development of the wind power in China can not onlymake improvement in the optimization of the national energy mix and the protectionof the deteriorating environment, but also help promote the stable and economicaloperation of the power system.The remarkable achievement in the construction oflarge-scale wind farms promotes the rapid development of wind power industry. Thewind power integration has prominent influence on the whole power system,particularly the voltage stability of the power system.The wind power system is adynamic system characterized by its strong nonlinearity and can be analyzed using thebifurcation theory, a powerful tool of studying the structural stability of nonlineardynamic systems. In this paper, the voltage stability of the power system containingwind farms is investigated and some kinds of bifurcations closely related to thevoltage instability are analyzed thoroughly. The research is as follows:(1) The dynamic and static equations for the general induction generators arederived and an applicable mathematical model is established for the wind generatorset composed of the general induction generators. The influence of the wind velocityfluctuation in wind farms on the active-reactive operating characteristic of theinduction generators and the impact of the variation of wind turbine’s output power onthe system voltage are analyzed. Furthermore, the effect mechanism of wind farms onthe voltage stability of local power grid is achieved. The study shows a large numberof reactive power absorbed by wind farms results increasing reactive powertransporting from grid to wind farms, and then larger line voltage drop reduces windfarms voltage stability.(2) A multi-parameter continuation tracking algorithm is proposed to calculatethe bifurcation boundaries or hyper-surface, the influence of the active power outputfluctuation of wind farms and the static var compensator on the voltage stability of thewind power system composed of general induction generators is analyzed, theinfluence of the injection of active power of wind farms and the static varcompensator control parameters and the excitation system parameters on thesaddle-node bifurcation is discussed. The quadratic polynomial nonlinear analytical expression method proposed is capable of describing the saddle-node bifurcationboundary and hyper-surface of the parameter space analytically. The simulationverifies the accuracy and effectiveness of the method.(3) The influence of the power parameters of wind farms and the static varcompensator parameters on the Hopf bifurcation point is analyzed and the relationshipbetween wind farm active power output and wind farms power system voltagestability is obtained. From the view of the structural stability, the static varcompensator control effect on system characteristic polynomial is analyzed and themechanism of the static active power compensation improving dynamic voltagestability is obtained.The study shows the static var compensator improves the busvoltage immunity and strengthen the system equilibrium point stability by adjustingthe local system structural parameters, which can delay the Hopf bifurcation andimprove the dynamic stability of the nonlinear power system voltage.(4) The control strategy for the Hopf bifurcation which combines the static varcompensator and the linear feedback control method together is proposed，the linearfeedback controller of Hopf bifurcation for the conventional power system and thepower system including wind farms is designed. The simulation result verifies theeffectiveness of the Hopf bifurcation controller on the Hopf bifurcation and improvesthe dynamic voltage stability of the system.Multi-parameter bifurcation analysis is better to reveal stability bifurcationmechanism caused by paramete variation of wind farms and the static varcompensator, which contributes to the theory and application value of the bifurcationcontrol to the nonlinear powers system voltage stability containing wind farms.更多还原