【作者】 闫庆方；

【导师】 刘宪林；

【作者基本信息】 郑州大学 ， 电力系统及其自动化， 2009， 硕士

【摘要】 交流励磁水轮发电机组是一种新型的水力发电设备,其发电机由变频电源提供对称交流励磁,且可根据要求对励磁电压的幅值、频率和相位加以控制,因此可以控制发电机励磁磁场的大小及其相对转子的位置和电机转速,使得交流励磁水轮发电机组具有变速恒频运行能力、较强的进相运行能力、独立的有功与无功调节能力和良好的稳定性。与普通的同步发电机组相比,交流励磁水轮发电机组可以灵活地调节有功、无功,提高系统的稳定性。此外,通过发电机励磁与水轮机调速的协调控制,水轮机可在水头、流量变化时运行于最优转速,实现变速优化运行,从而提高水能利用效率,节约用水,提升机组运行效益。因此,对交流励磁水轮发电机组进行稳定性和经济性研究具有十分重要的现实意义。本文围绕交流励磁水轮发电机组运行的稳定性和经济性开展研究,主要的工作内容和成果如下:(1)作为交流励磁水轮发电机组运行稳定性和经济性分析计算的基础性工作,进行模型研究。在转子磁场dq0坐标系下的交流励磁发电机模型的基础上,进一步详细推导和阐述了该坐标系下交流励磁发电机的五阶和三阶实用模型以及采用定子电压定向矢量控制策略的励磁系统模型。综合有关成果,建立了水轮机的线性化模型和PID控制策略下的水轮机调速系统模型;建立了具有引水管道、尾水管和尾水洞的复杂输水系统的弹性水击等值电路模型。(2)对交流励磁水轮发电机组提升电力系统平稳性和稳定性问题进行仿真研究。基于交流励磁发电机实用模型、励磁系统模型、水轮机一输水系统模型和调速系统模型,在Matlab/Simulink下建立了交流励磁水轮发电机组的整体仿真模型。对含交流励磁水轮发电机组的单机无穷大系统和多机系统,分别进行了负荷调整小扰动和短路故障暂态过程仿真。结果表明,与普通同步发电机组相比,交流励磁水轮发电机组不仅有功和无功可以独立调节、响应速度快,而且可以显著提高电力系统的稳定性。(3)交流励磁水轮发电机组可变速运行的特点为提升水轮发电机组的节水和运行效益提供了可能。本文对此进行深入研究,在对水轮机综合特性曲线进行拟合的基础上,提出了基于遗传算法的交流励磁水轮发电机组转速优化方法,并结合工程实例对不同水头和出力下交流励磁水轮发电机组变速运行的效率、消耗水量和多发电效益进行了计算分析。结果表明,本文所提出的交流励磁水轮发电机组转速优化方法具有较高的计算精度;与常规水轮发电机组相比,交流励磁水轮发电机组具有显著的节水和多发电效益。更多还原

【Abstract】 ACEHU (AC Excited Hydrogenerator Unit) is a new type of hydro-electric power equipment, with the inverter power providing generator with symmetrical AC excitation, and the amplitude, frequency, and phase of the excitation voltage being controlled in accordance with the requirements. The size of the magnetic field excitation, the location of the rotor and the motor speed can be controlled, so that the ACEHU has VSCF (Variable Speed Constant Frequency) power generation and deep condensive operational capabilities, independent active and reactive power regulation capacity and good stability. Compared with the traditional SGU (synchronous generator unit), the ACEHU can flexibly adjust reactive and active power and improve the system’s stability. In addition, through the coordinated control of generator excitation and hydroturbine speed governing, the hydroturbine can operate around the optimal speed during the time of head and flow rate changes, achieve its optimal operation of variable speed, and then improve water use efficiency, save water and enhance effectiveness of unit operation. Therefore, it is of great practical significance to study the stability and economical efficiency of the ACEHU. So this thesis is devoted to the stability and economical efficiency study of ACEHU operation, and its main contents and achievements are as follows:(1) Model study is conducted as the basis for analyzing and calculating ACEHU operation stability and economical efficiency. Based on the ACEG(AC Excited Generator) mathematical model under the rotor magnetic field dq0 coordinates, corresponding fifth-order and third-order practical model under the rotor magnetic field dq0 coordinates is further detailed derived and explained, and the excitation system model under the stator voltage-oriented vector control strategy is established. Integrated related results, the linear hydroturbine model and the model of hydroturbine speed governing system under PID control strategy are established; the elastic water-hammer equivalent circuit model of the complexity conduit system with pipeline, tailrace and tailrace tunnel is established.(2) The simulation research on ACEHU improves power system stationarity and stability is done. Based on the ACEG practical model, control model of excitation system, hydroturbine model, conduit system model and speed governing system model, the simulation model of the ACEHU is set up under the Matlab/Simulink. For the SMIB (single machine infinite bus) system and the multi-machine system containing the ACEHU, load adjustment of small disturbance and short-circuit fault of transient process simulation are separately conducted. The results show that compared to the traditional SGU, the ACEHU can achieve independent active and reactive power regulation, fast response, and can significantly improve power system stability.(3) The characteristic of variable speed operation of the ACEHU makes it possible to improve water saving and operation effectiveness of the hydrogenerator unit. In this dissertation, the further study of water saving and operation effectiveness is done. Based on the hydroturbine integrated characteristic curve fitting, the method of using Genetic Algorithm to find speed optimization of ACEHU is proposed. A calculation analysis is made on the efficiency, water consumption and power generation effectiveness of the ACEHU variable speed operation when it is under different head and power conditions. The results show that the method to find speed optimization of ACEHU which is proposed in this dissertation has high calculation accuracy; compared to the traditional hydrogenerator unit, the ACEHU has significant benefit of water-saving and more power generation.更多还原