双馈风电场经串补并网引起的次同步振荡分析与监控

发布时间：2018-03-20 16:32

本文选题：双馈感应风力发电机　切入点：次同步振荡　出处：《南京理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：近年来,风能作为一种可持续的清洁能源在我国得到了迅猛的发展,但是由于我国地理条件比较特殊,风力发电中心远离负荷中心,因此需要远距离输电。串联电容补偿输电方式可以实现电能的远距离、大容量输送,是一种成熟而又经济的技术,在风电外送中得到了广泛的应用。然而,双馈感应风力发电机(DoubleFedInductionGenerator,DFIG)经过串补线路并网运行时,会导致系统发生次同步振荡(Sub-synchronous Oscillations,SSO)现象。风电场次同步振荡是电气系统和风电机组之间以低于系统同步频率的某个或多个频率显著交换能量,造成电压、电流及输出功率的振荡,并威胁风力发电机的安全和电力系统的稳定,因此对双馈风电场经串补并网系统的次同步振荡研究具有重要的理论与实际意义。首先建立了双馈感应发电机、串补输电线路的数学模型,对双馈风机的转子侧及网侧变流器的数学模型及控制策略作了详细的介绍,并推导出了影响双馈风机次同步振荡的主要因素。然后在实时数字仿真平台(Real Time Digital Simulator,RTDS)中搭建了含串补线路的风电并网系统模型,通过在仿真实验中改变风速、线路的串联补偿度、风机运行台数以及转子侧和网侧控制器的参数探讨风电场次同步振荡特性,总结出了风机在工作条件和运行参数变化时次同步振荡的规律。然后通过对风机汇集点电压、电流和功率进行傅里叶频谱分析,从中分离出了工频分量和次同步分量。由汇集点次同步振荡功率的方向和次同步电压与额定电压的关系组成了复合判据,对风电场中的主要振荡源进行有效的识别;根据线路电流中次同步分量大小建立了保护装置的启动判据和动作判据,并完成了次同步振荡保护样机的开发。最后通过继电保护仪加量完成了对样机的实验验证,实验结果表明:SSP-522次同步振荡监控装置计算准确,逻辑合理,动作迅速,达到了预定目标。
[Abstract]:In recent years, wind energy, as a kind of sustainable clean energy, has been developing rapidly in China. However, because of the special geographical conditions in China, wind power generation center is far away from load center. So long distance transmission is needed. Series capacitor compensation can realize long distance and large capacity transmission of electric energy. It is a mature and economical technology and has been widely used in wind power outputting. When DoubleFedInduction Generator (DFIGG) is connected to the grid through a series compensation line, The sub-synchronous oscillation of the wind farm is the significant exchange of energy between the electrical system and the wind turbine at one or more frequencies lower than the synchronous frequency of the system, resulting in oscillations in voltage, current and output power. It also threatens the safety of wind turbine and the stability of power system. Therefore, it is of great theoretical and practical significance to study the sub-synchronous oscillation of doubly-fed wind farm through series-compensated grid connected system. Firstly, a doubly-fed induction generator is established. The mathematical model of series compensation transmission line, the mathematical model and control strategy of rotor side converter and grid side converter of doubly fed fan are introduced in detail. The main factors influencing the sub-synchronous oscillation of doubly-fed fan are deduced, and then a wind power grid-connected system model with series compensation circuit is built in the real Time Digital simulator RTDSs, and the wind speed is changed in the simulation experiment. Discussion on the subsynchronous oscillation characteristics of wind farm, the series compensation degree of the line, the number of fan operating stations and the parameters of the rotor side and grid side controllers, The law of sub-synchronous oscillation of fan when its working conditions and operating parameters are changed is summarized. Then the Fourier spectrum analysis of the voltage, current and power of fan gathering point is carried out. The power frequency component and the sub-synchronous component are separated from each other. The composite criterion is composed of the direction of the sub-synchronous oscillation power and the relation between the sub-synchronous voltage and the rated voltage, which can effectively identify the main oscillation sources in the wind farm. According to the magnitude of the sub-synchronous component in the line current, the starting criterion and the action criterion of the protection device are established, and the development of the sub-synchronous oscillation protection prototype is completed. Finally, the experimental verification of the prototype is completed through the addition of the relay protection instrument. The experimental results show that the control device of the SSP-522 synchronous oscillation is accurate, logical and quick, and achieves the predetermined goal.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM614;TM712

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