交直流混联电力系统的动态模型与广域阻尼控制策略研究

发布时间：2018-11-02 20:02

【摘要】：随着我国大规模交直流互联电力系统的逐步形成,电网结构发生了深刻变化,整个系统运行状况呈现出新特性。能源中心向负荷中心输电距离长,线路负荷重,区域间的低频振荡问题时有发生,严重制约了线路传输容量上限,威胁着整个电力系统的安全稳定运行。低频振荡问题的特征值分析方法依赖于根据机理所建立的系统详细模型,随后在其工作点附近对其进行线性化处理,最后根据其特征值以及特征向量等进行分析。目前,大部分商用系统分析软件均采用此种低频振荡分析手段。但是,由于系统元件的地区差异以及新元件的不断投入运行,商业分析软件提供的动态元件模型库并不能完全满足实际工程需求。因此,完善软件的动态模型库是实现低频振荡问题分析的基础,具有较高的工程实际应用价值。伴随着广域量测技术的发展,依据量测信息实现低频振荡问题的监测、分析和控制的技术手段发展迅猛。量测信息反映着系统的实际运行工况,所以根据量测信息利用辨识技术建立的系统模型更直接的反映了系统实际运行特性,基于辨识模型的分析与控制器设计方法具有重要实际意义。但是,传统的辨识方法在精度上有待进一步提高,并且对于大量的可控元件,如何从中选取以实现系统阻尼最大化有待研究。本文针对PSS/E动态元件库无法满足实际工程需求的问题,对比了 BPA与PSS/E动态元件库的差异,在PSS/E中建立了无法对应上BPA的励磁系统、原动机调速器以及电力系统稳定器等模型,并通过单机无穷大系统的仿真验证了建立模型的正确性。针对区域间低频振荡问题,提出了一种基于多元线性回归的电力系统状态空间模型辨识方法,通过对数学模型以及电力系统的辨识对比,证明所提方法较子空间方法有更高的精度;利用所提辨识方法,建立了算例系统和某实际电网的降阶状态空间模型,基于辨识所得模型,利用几何指标选取最佳的控制器装设位置,并通过相位补偿方法设计了直流阻尼控制器,算例系统以及实际系统的仿真结果表明,本文所提直流阻尼控制器方法能够选出最佳装设位置,显著提高系统阻尼。
[Abstract]:With the gradual formation of large-scale AC / DC interconnected power systems in China, the power network structure has undergone profound changes, and the operation of the whole system presents new characteristics. The transmission distance from the energy center to the load center is long, the line load is heavy, and the problem of low frequency oscillation between regions occurs from time to time, which seriously restricts the upper limit of transmission capacity of the transmission line and threatens the safe and stable operation of the whole power system. The eigenvalue analysis method of low frequency oscillation problem depends on the detailed model of the system established according to the mechanism, then linearized it near its working point, and finally it is analyzed according to its eigenvalue and eigenvector. At present, most commercial system analysis software uses this low frequency oscillation analysis method. However, because of the regional differences of the system components and the continuous operation of the new components, the dynamic component model base provided by the commercial analysis software can not fully meet the actual engineering needs. Therefore, improving the dynamic model base of software is the foundation of low frequency oscillation problem analysis, and has high practical application value. With the development of wide-area measurement technology, the monitoring, analysis and control of low-frequency oscillation problem based on measurement information develop rapidly. The measurement information reflects the actual operating conditions of the system, so the system model based on the identification technology based on the measurement information reflects the actual operating characteristics of the system more directly. The analysis and controller design method based on identification model has important practical significance. However, the accuracy of the traditional identification method needs to be further improved, and for a large number of controllable elements, how to select them to maximize the damping of the system remains to be studied. In this paper, aiming at the problem that PSS/E dynamic component library can not meet the actual engineering requirements, the difference between BPA and PSS/E dynamic component library is compared, and the excitation system which can not correspond to BPA is established in PSS/E. The model of prime mover governor and power system stabilizer is verified by simulation of single machine infinite bus system. In this paper, an identification method of power system state space model based on multiple linear regression is proposed to solve the problem of inter-region low frequency oscillation. The mathematical model and power system identification are compared. It is proved that the proposed method has higher accuracy than the subspace method. By using the proposed identification method, the reduced-order state space model of an example system and a practical power network is established. Based on the identified model, the optimal location of the controller is selected by using geometric indexes. The DC damping controller is designed by the phase compensation method. The simulation results of the example system and the actual system show that the DC damping controller proposed in this paper can select the best installation position and increase the system damping significantly.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM712

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