大电源外送系统次同步振荡分析方法及特性研究

发布时间：2018-05-01 16:39

本文选题：大电源外送系统 + 次同步振荡　；参考：《华中科技大学》2014年博士论文

【摘要】：我国的能源资源和电力负荷分布状况决定了我国“西电东送,北电南送”的大规模、远距离输电发展格局。为提高输送容量,大型电源基地外送系统广泛采用了串联电容补偿和高压直流输电技术,系统具有近电气距离多机和交/直流多通道等特点,机电耦合特性异常复杂,次同步振荡(Subsynchronous Oscillation, SSO)问题凸显,采用常规的单机无穷大简化等值系统难以准确揭示其次同步振荡特性。另一方面,随着柔性交流输电系统(Flexible AC Transmission Systems, FACTS)的逐步推广和应用,以及我国西北地区风电的大规模开发和并网,我国电力系统的次同步振荡问题更将呈现出新的特点。本论文结合上述工程背景,研究多机交直流联合电力系统次同步振荡分析的特征值和复转矩系数分析方法,探索含FACTS及风电的大电源外送系统次同步振荡特性。论文的主要工作和研究成果如下。 (1)研究了电力系统次同步振荡特征值分析中网络部分状态空间的生成方法。针对具有非常态网络(Improper Network)特点的输电网状态空间生成所面临的独立状态变量选取等问题,归纳了输电网络状态变量选取规律,定义了电容支路动态导纳矩阵的概念,进而采用支路追加的思想提出了一种建立电力系统网络部分状态空间模型的新方法；该方法可方便地根据网络结构确定网络状态变量,且算法易于实现；工程实际算例特征值分析和时域仿真表明了该方法的有效性。 (2)改进了基于复频域端口等效导纳矩阵(Complex Frequency Domain Port-equivalence Conductance Matrix, CPCM)的复转矩系数法并开发了相应软件。系统地研究了电力系统元件和网络的复频域建模方法,改进了基于CPCM的复转矩系数法中发电机和网络复频域模型的接口算法,从而使算法可有效地计及多机系统中机组轴系间的耦合作用,提高了电气复转矩系数计算的准确性,并使算法具有分析含发电机转速反馈控制的SSO阻尼装置对机组电气复转矩系数影响的能力；工程实际算例特征值分析和时域仿真均验证了改进算法的有效性。所开发的分析软件可为系统规划／运行中的次同步振荡问题研究提供一种有效的分析手段。 (3)以我国某工程系统为原型系统,采用改进的基于CPCM的复转矩系数法研究了含TCSC (Thyristor Controlled Series Capacitor)的交直流联合电力系统的次同步振荡特性,并对比分析了系统中串补线路分别采用TCSC和固定串联电容补偿时系统的次同步振荡特性。分析表明有以下特点可供大电源外送工程规划和运行参考：经交直流联合通道外送的SSO风险小于仅经串联电容补偿外送的风险,且在串联电容补偿输电系统中推广TCSC的使用可降低系统的SSO风险。 (4)我国西北地区存在密集的大容量风电和火电集中外送的需求,风电—火电打捆集中外送系统的工程实现将成为必然。针对风电—火电打捆经串补外送系统的次同步相互作用(Subsynchronous Interaction, SSI)新问题,汽轮发电机组和风电机组间SSI特性的相互影响研究表明风电—火电打捆可对汽轮发电机组和风电机组的SSI问题有一定改善作用,并进一步探索了DFIG (Doubly Fed Induction Generator)附加控制综合抑制系统中汽轮发电机组SSO和风电机组SSI的方法和可行性。
[Abstract]:In order to improve the transmission capacity, the series capacitance compensation and high voltage direct current transmission technology are widely adopted in the large power supply base outgoing system. Channel and other characteristics, mechanical and electrical coupling characteristics are very complex, Subsynchronous Oscillation, SSO problems are highlighted, the use of conventional single machine infinity simplified system is difficult to accurately reveal the second synchronization oscillation characteristics. On the other hand, with the gradual extension of the flexible AC transmission system (Flexible AC Transmission Systems, FACTS) With the large-scale development and grid connection of wind power in the northwest of China, the sub synchronous oscillation of the power system in China will take on new characteristics. This paper combines the above engineering background to study the eigenvalues and the complex torque coefficient analysis method for the sub synchronous oscillation analysis of the multi machine AC and DC joint power system, and explore the FACTS and wind power. The main work and research results of the paper are as follows.
(1) the generation method of the network part state space in the eigenvalue analysis of the subsynchronous oscillation of the power system is studied. In view of the independent state variable selection for the state space generation of the transmission network with the characteristic of the Improper Network, the selection law of the state variable of the transmission network is summed up and the dynamic capacity branch path is defined. The concept of admittance matrix is introduced, and a new method of building a partial state space model of power system network is proposed by using the idea of branch addition. The method can easily determine the network state variables according to the network structure, and the algorithm is easy to be realized. The effectiveness of the method is demonstrated by the analysis of the eigenvalues and the time domain simulation in the practical engineering examples.
(2) the complex torque coefficient method based on the complex frequency domain port equivalent admittance matrix (Complex Frequency Domain Port-equivalence Conductance Matrix, CPCM) is improved and the corresponding software is developed. The complex frequency domain modeling method for power system components and networks is systematically studied, and the generator and network complex in the complex torque coefficient method based on CPCM are improved. The interface algorithm of the frequency domain model enables the algorithm to effectively calculate the coupling effect between the units in the multi machine system, improve the accuracy of the calculation of the electrical complex torque coefficient, and make the algorithm have the ability to analyze the influence of the SSO damping device with the generator speed feedback control on the electrical complex moment coefficient of the unit; the actual engineering example is special. Both eigenvalue analysis and time domain simulation verify the effectiveness of the improved algorithm. The developed analysis software can provide an effective method for the study of sub synchronous oscillation in system planning / operation.
(3) taking a engineering system in our country as a prototype system, a modified CPCM based complex torque coefficient method is used to study the sub synchronous oscillation characteristics of the AC / DC joint power system with TCSC (Thyristor Controlled Series Capacitor). The system is compared and analyzed in the system with TCSC and fixed series capacitor compensation in the system. The characteristics of synchronous oscillation show that the following characteristics can be used as reference for the project planning and operation of large power supply. The risk of SSO transmission through AC and DC joint channels is less than the risk of compensating external transmission only by series capacitance, and the use of TCSC in the series capacitor compensation transmission system can reduce the SSO risk of the system.
(4) there is a dense large capacity wind power and centralized outgoing demand in the northwest of China, and the implementation of wind power and thermal power bundling centralized outflow system will be inevitable. The new problem of Subsynchronous Interaction, SSI, steam turbine generator and wind turbine is a new problem for wind power and thermal power bundling. The study on the interaction of SSI characteristics between groups shows that wind power and thermal power bundling can improve the SSI problem of turbogenerator and wind turbine, and further explore the method and feasibility of DFIG (Doubly Fed Induction Generator) additional control integrated control system of SSO and wind turbine SSI.

【学位授予单位】：华中科技大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM712

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