电力系统机电动态过程中时变幅频内电势激励下的功率特性  

Power Characteristics With Excitation of Time-varying Amplitude-frequency Internal Voltages During Electromechanical Dynamic Process in Power Systems

作　　者：杨晖[1] 袁小明[1] YANG Hui;YUAN Xiaoming(State Key Lab of Advanced Electromagnetic Engineering Technology,Huazhong University of Science and Technology,Wuhan 430074,Hubei Province,China)

机构地区：[1]强磁场工程与新技术国家重点实验室(华中科技大学),湖北省武汉市430074

出　　处：《中国电机工程学报》2021年第9期3079-3089,共11页Proceedings of the CSEE

基　　金：国家自然科学基金委–国家电网公司“智能电网联合基金”集成项目(U1866601);重点支持项目(U1766202);Project Supported by National Natural Science Foundation of China(NSFC)-State Grid Corporation of China(U1866601;U1766202)。

摘　　要：机电动态过程中,伴随着励磁及转子转速的变化,电力系统各台发电机内电势节点幅值和频率均为时变量。建立各台发电机输出的功率与各内电势节点状态的解析化关系(即电力系统的功率特性方程),是分析大系统机电动态过程及其稳定性的基础。目前相关研究大多是基于相量来描述内电势进而建立与功率的关系,因为受到"准稳态"假定的限制,所以不能反映出各内电势节点的频率这一状态的变化对发电机输出功率变化的影响。针对这一问题,该文基于瞬时幅值和瞬时频率描述内电势,根据线路电感元件的时域积分方程首先刻画功率与内电势节点状态的原始解析关系;然后,通过对原始关系进行适当简化,在两机系统中建立用于机电动态过程研究的功率特性方程。该方程能反映出系统中各内电势节点的幅值及频率等状态的变化对发电机输出功率变化的影响,不受"准稳态"假定束缚,并且数学形式简洁,具有工程实用价值。最后,在Matlab/Simulink中验证了所建功率特性方程的有效性,并讨论了拓展至多机系统的基本思路。In the electromechanical dynamic process, with the changes of excitation and rotor speed, the amplitude/frequency of the internal voltage for synchronous generator both varied with time. Establishing the analytical relation between the output power of generator and the states of each internal voltage node, viz. power characteristic equation, was the basis of analyzing the dynamic process and the system stability. Now, most of the researches used phasors to describe the internal voltages and then established the power equation, which failed to take the effect of frequency variation on power dynamic into account owing to the quasistationary assumption. To solve the problem, this paper described the internal voltage with the instantaneous amplitude/frequency, and the original relation between the output power of generator and the states of node was first obtained according to the line’s integral equation. Then, by properly simplifying the original relation, the power characteristic equation suitable for the study of electromechanical dynamic process was established in the two-machine system. This equation can reflect the effect of node’s amplitude/frequency variation on the power output, which was not bound by quasi-stationary assumption. It was also simple in form, which had engineering practicability. Finally, the validity of the established equation was verified in Matlab/Simulink, and the basic idea of extending it to the multi-machine system was also discussed.

关 键 词：电力系统功率特性 内电势 交流输电线路 机电动态过程 瞬时频率 

分 类 号：TM71[电气工程—电力系统及自动化]