【作者】 张德栋；

【导师】 邱家俊；

【作者基本信息】 天津大学 ， 一般力学与力学基础， 2004， 硕士

【摘要】 随着大规模电力系统的发展，电力系统的结构日益复杂.各种电气控制元件的应用和大规模电网的连接，使得机电耦联振动问题和电力系统稳定性问题更加突出。本文采用机电耦联振动系统的理论和非线性系统分岔的理论，对三峡发电机组进行了理论和数值计算，研究了发电机、网机系统由电磁参数引起的稳定与分岔问题。本文的研究内容和主要成果有以下几个方面。(1) 综述了机电分析动力学研究的发展和研究方法，对电力系统的动态过程和非线性系统振动与分岔的基本概念做了简要叙述。(2) 从电机学和机电分析动力学两种角度出发,最终建立了相同的发电机耦合扭振系统的微分动力方程。证明了发电机系统的机械与电量由能量统一到了一起，且相互影响。机电分析动力学为机电耦联系统研究提供了一个有力的工具。(3) 系统研究了发电机组三相短路、两相线间短路、一相对中短路三种特殊运行状态对于整个系统振动的影响和给发电机电流、功率角带来的暂态冲击。研究了特殊运行状态下，不同短路点(发电机端、无穷大电网端)对系统影响程度的大小。总结了不同短路状态下，系统固有频率的变化分布规律。最后讨论了非同期合闸时，非同期角的不同带来的电流及电磁力矩的冲击，绘制出了非同期角的大小与瞬态电磁力矩最大值的关系曲线.(4) 研究了在水轮机外激励与发电机、输电线路中电磁参数的共同作用下，整个机电耦联系统所特有的几种共振现象。指出功率角δ 和转子角速度ω4为机械和电气两个部分相联系的关键变量，另外的变量如：α1、α2、α3、ω1、ω2、ω3及各电流项则是通过ω4、δ 来互相影响的。(5) 通过数值计算得到了系统在双参数改变情况下系统的稳定区域图，对不同区域内的特征点进行了数值验证，研究了参数变化下，系统特征值的变化规律。(6) 根据模态不变流形的理论，对系统存在两个正实特征根的情况下的高维非线性动力方程进行降维，得到了在一定程度上能反映系统动力学特性的动力学方程，为今后的研究打下基础。更多还原

【Abstract】 With the development of power system, the structure of power system nowadaysis becoming more and more complex. The application of various electrical controllersand the union of large scale power network make the nonlinear vibration ofmechanical and electrical coupled systems and stability of power system a key factorto analyze the system thoroughly. Using the theory of nonlinear dynamics ofmechanical and electrical coupled systems and bifurcation theory of nonlinear system,based on the generator set in Three Gorges, the theoretical and numerical calculationare presented to analyze the stability and bifurcation phenomena with electromagneticparameter change. Major work and results obtained are as follows: (1) A review is given on the development and methods of analysis. A briefdepiction is given too on the basic concepts not only about the dynamic process ofpower system but also about the nonlinear vibration and bifurcation. (2) According to two different opinions : electromechanics and analytic dynamicsof mechanical and electrical systems, we obtained the same differential dynamicalequations of the whole system. It proved that the energy combined the mechanical andelectrical parts to a coupled system in which the variables affect each other. analyticdynamics of mechanical and electrical systems provides a useful tool for analysis ofnonlinear system. (3) We expatiated three kind of symmetry or asymmetry failure, which are threephase short-circuit, two phase short-circuit and one phase short-circuit, to find theinfluence on the vibration of system, currents and power angle. We also studied theinfluencing extent on system with different location where short-circuit take place.Then, we sought the law of initial frequencies and studied the transient responses ofcurrents and electromagnetic torque in out-of-phase synchronization. We got the curvebetween the angle of out-of-phase and maximum of transient torque. (4) Considering the co-action of turbine exciting and parameters of generator andelectric transmission line, we studied several kinds of special resonance phenomena inmechanical and electrical coupled system. We noted that power angle δ and angularvelocity of rotor ω4 are the key variables that linked other mechanical or electricalvariables and caused them to interact each other. (5) Through numerical calculation, we obtained the stability figure for whole<WP=5>system with two parameters changing simultaneously. We have tested the characterpoints by numerical calculation and find the law of eigenvalues of system. (6) Based on the theory of nonlinear normal modes, we reduced the dimension ofhigh dimension nonlinear system when it has two positive real eigenvalues. Thesimplified equations can reflect the dynamic behavior to some extent, which will behelpful for the future research.更多还原