弱送端风光火打捆交直流外送系统小干扰功角稳定性研究

发布时间：2018-07-26 10:06

【摘要】：在我国的西北地区,随着风电和光伏等清洁能源开发规模的扩大,多个大容量跨区特高压直流工程陆续投产,西北电网稳定特性正在发生深刻变化,局部弱送端的网架特征日益凸显。同时由于我国能源资源和能源需求逆向分布的客观现实,风光火三种能源均存在大规模、远距离输送至东部和中部负荷中心的客观需要。对于弱送端风光火打捆交直流外送系统,由于系统各模块的交互影响,使得系统的稳定性分析变得更加的复杂。对此,本文围绕弱送端风光火打捆交直流外送系统小干扰功角稳定性展开了研究。首先本文建立双馈感应发电机,光伏发电站和直流输电系统的动态简化模型,设计了各动态模型的控制策略,根据所建立的动态模型推导了各模块的线性化模型,并根据李雅普诺夫线性化方法,建立了风光火打捆交直流外送全系统的线性化模型。其次本文介绍了系统状态矩阵的特征分析方法,以此为理论依据,在仿真系统中探究了影响系统小干扰功角稳定性的四个因素,包括送端系统各电源之间的电气距离、交直流输电线的长度、交直流传输容量的比例和风光火各电源的并网容量,并分别分析了这四个因素对系统小干扰功角稳定性的影响。随后,为改善风光火打捆交直流外送系统的阻尼,提出在双馈风机有功控制环附加PSS,并通过鱼群算法设计PSS参数,证明其能提高系统阻尼;提出在光伏电厂DC/AC换流器有功控制环附加PSS,并通过鱼群算法设计PSS参数,证明其能提高系统阻尼;提出在直流整流侧定电流控制环附加PSS,并通过鱼群算法设计PSS参数,证明其有效性。最后为避免多台PSS相互之间的不利影响,采用鱼群算法对多台PSS的参数进行协调设计,尽可能的提高系统阻尼。
[Abstract]:In northwest China, with the expansion of the scale of clean energy development, such as wind power and photovoltaic, a number of large-capacity trans-area UHVDC projects have been put into production one after another, and the stability characteristics of the Northwest Power Grid are undergoing profound changes. The characteristic of the local weak terminal is becoming more and more prominent. At the same time, due to the objective reality of reverse distribution of energy resources and energy demand in China, there is an objective need for large-scale transportation of all three kinds of energy sources to the eastern and central load centers. The stability analysis of the system becomes more complex because of the interaction of each module of the system. In this paper, the stability of the small disturbance angle of the AC / DC outgoing transmission system is studied. Firstly, the dynamic simplified model of doubly-fed induction generator, photovoltaic power station and direct current transmission system is established, and the control strategy of each dynamic model is designed. According to the established dynamic model, the linearization model of each module is derived. Based on the Lyapunov linearization method, the linearization model of the whole AC / DC system is established. Secondly, this paper introduces the characteristic analysis method of system state matrix, based on which, four factors which affect the stability of power angle of the system with small interference are explored in the simulation system, including the electrical distance between the power sources of the terminal system. The length of AC / DC transmission line, the ratio of AC / DC transmission capacity and the grid-connected capacity of each power source are analyzed, and the influence of these four factors on the stability of the system with small interference angle is analyzed. Then, in order to improve the damping of AC / DC transmission system with wind and fire bundles, it is proposed to add PSSs to the active power control ring of doubly-fed fan, and the PSS parameters are designed by the fish swarm algorithm, which proves that the damping of the system can be improved. The active power control loop of DC/AC converter in photovoltaic power plant is put forward, and the PSS parameter is designed by fish swarm algorithm, which proves that it can improve the system damping, and the fixed current control loop on DC rectifier side is added to the control loop, and the PSS parameter is designed by fish swarm algorithm. Prove its validity. Finally, in order to avoid the adverse effects of multiple PSS, fish swarm algorithm is used to coordinate the design of the parameters of multiple PSS to improve the damping of the system as much as possible.
【学位授予单位】：华北电力大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM712

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