【作者】 张涛；

【导师】 蔡国伟；

【作者基本信息】 东北电力大学 ， 电力系统及其自动化， 2008， 硕士

【摘要】 大区域电网的互联是低频振荡容易发生的一个不可忽视的因素。在线的振荡特性分析是实现电力系统低频振荡在线监视以及广域阻尼控制的重要理论基础。基于全球定位系统(GPS)的广域测量系统(WAMS)的发展和应用为在线分析低频振荡模式乃至控制提供了新契机。利用振荡曲线分析系统振荡信息已经得到广泛的应用。在互联的多机电力系统中,存在多种振荡模式,需要重点关注的是区域间的主导弱阻尼或负阻尼模式。在实际的多机系统中,由于外界的干扰因素很多,如噪声等因素,这给常规的信号辨识带来不便。利用振荡曲线提取多机振荡信息,需要选择合适的曲线,才能快速得到系统主导振荡模式。首先,从同调机群识别角度研究了扰动下大区域电网低频振荡的本质与原因等问题。本文给出一种基于模糊划分的迭代自组织数据分析技术(ISODATA)的模糊聚类方法,在一些基本假设和对系统做了必要验证的基础上,形成同调识别模糊集合,用模糊聚类迭代方法进行分群,直到得到满意的分类结果为止。其次,在多机系统同调分群的基础上研究了动态分割理论。本文介绍了动态分割理论的基本概念,然后提出“分而不割”的方法来选择合适的低频振荡信号曲线。该理论揭示了网络之间的弱联系,为寻找合适的振荡曲线提供了重要的理论价值。最后,采用Prony分析算法从选择的曲线中准确地提取主导振荡模式。为进一步验证所提方法的正确性,通过对EPRI 8机36节点系统的算例仿真,验证了该方法的可行性和有效性。更多还原

【Abstract】 The wide range electrical network interconnection is a noticeable factor which the low-frequency oscillation is easy to occur. Online oscillation characteristic analysis is the important academic foundation for achieving online detection and damping control of low-frequency oscillations, while the application and development of wide-area measurements based on Global Positioning System (GPS) have provided a new approach for online identification and control of low-frequency oscillation modes. It has already obtained the widespread application analyzing power system oscillation information by the oscillation curve.There are different low-oscillation modes in inter-area system, while the dominant low damping or negative mode should be focused on. In a practical multi-machine power system, a lot of extrinsic disturbance factors, take noise for example, make natural signal identification discommodious. It is needed to select appropriate swing curve to identify the area dominant mode.First of all, the essence and cause of low-frequency oscillation in an interconnected bulk power system are researched from the coherent generators identification. The principle of iterative self-organizing data analysis techniques algorithm (ISODATA) fuzzy clustering method based on fuzzy partition is presented. Then, on the basis of fundamental assumption and necessary system provability the fuzzy set is formed, while power system is partitioned by the iterative method until the satisfying result comes out.Then, dynamic partition theory based on the coherent generators identification in the multi-machine power system is researched. The article mostly introduces basal concepts of dynamic partition theory, then advances the divide and not been partitioned method for the appropriate low-frequency oscillation signal. The theory shows weak link of network, and gives the importance academic value in looking for appropriate swing curve.Finally, Prony method can be accurate to abstract the area dominant oscillation modes from the appropriate low-frequency oscillation signal to reveal the interaction of mode in complex oscillation. For validating the method that is advanced, the feasibility and efficiency of the proposed method are verified on the EPRI 36-bus AC system.更多还原