利用SVC附加控制抑制电网低频振荡的研究

发布时间：2018-08-18 09:11

【摘要】：伴随大区域电力系统的联接和大量快速励磁系统的使用，电力系统的机电振荡模式阻尼存在减小的风险，一定程度上加大了引发低频振荡的可能。从而，限制了电网关键联络线所能传输的电能，影响了电网的经济有效运行。并且伴随大规模风电的不断接入，风电场对电网稳定性的影响逐渐增大。因此，如何通过适当的控制措施来有效抑制电网低频振荡成为当前的研究重点。本文以SVC为例，，研究了其附加阻尼控制器对电网低频振荡的抑制效果，分析了SVC各控制环节的交互影响，提出了基于内嵌式神经网络的改进遗传算法的控制器多控制环节、多阻尼控制器的协调优化方法，进行了SVC广域附加阻尼控制器的设计及相关系统时滞稳定性研究。本文首先研究了SVC多控制环节的相互影响，证明了SVC阻尼控制与电压调节环节的交互作用，并提出基于内嵌式BP神经网络的改进遗传算法的SVC多控制环节协调优化方法。同时内嵌式神经网络的遗传算法具有节约计算时间、适用范围广等优点，为寻优计算中需要调用复杂计算的一类问题提供了一种有效的解决方案。为提高电网整体动态稳定性，以电网多运行方式下多振荡模态最小阻尼比最大化为优化目标，提出一种基于内嵌式Adaboost-BP神经网络的改进遗传算法的多运行方式下多机PSS及SVC附加阻尼控制器协调优化方法，其中内嵌式神经网络通过知识学习的方法将寻优过程中小扰动特征值分析计算分离出来，从而提高遗传算法的寻优计算效率。基于四机两区域系统及某地区大型互联电网的仿真也验证了该方法的有效性及优越性。基于Prony分析的主模比指标计算法选择SVC广域附加阻尼控制器的输入信号，并采用基于内嵌式Adaboost-BP神经网络的改进遗传算法优化设计其参数。采用子空间辨识法对系统进行降阶辨识，以四机两区域系统为例，建立考虑时滞的广域电力系统模型。利用基于自由权矩阵的时滞系统稳定性判据，研究含广域附加阻尼控制器的广域系统的时滞稳定性，并计算获得系统的时滞稳定裕度。
[Abstract]:With the connection of large area power system and the use of a large number of fast excitation systems, the electromechanical oscillation mode damping of power system has the risk of reducing, which increases the possibility of triggering low frequency oscillation to a certain extent. Therefore, it limits the electric energy that can be transmitted by the key tie-line, and affects the economic and effective operation of the grid. With the continuous access of large scale wind power, the influence of wind farm on power grid stability is gradually increasing. Therefore, how to effectively suppress the low-frequency oscillation through appropriate control measures has become the focus of current research. In this paper, taking SVC as an example, the suppression effect of its additional damping controller on the low frequency oscillation of power network is studied, and the interactive effect of each control link of SVC is analyzed, and an improved genetic algorithm based on embedded neural network is proposed for multi-control of the controller. Based on the coordinated optimization method of multi-damping controller, the design of SVC wideband additional damping controller and the research of time-delay stability of related systems are carried out. In this paper, the interaction of SVC multi-control links is studied, the interaction between SVC damping control and voltage regulation is proved, and an improved genetic algorithm based on embedded BP neural network is proposed to optimize the coordination of SVC multi-control links. At the same time, the genetic algorithm of embedded neural network has the advantages of saving computation time and wide application range, which provides an effective solution for a class of problems that need to call complex computation in optimization calculation. In order to improve the overall dynamic stability of the power network, the optimal objective is to maximize the minimum damping ratio of multi-oscillation modes under multi-operation mode. An improved genetic algorithm based on embedded Adaboost-BP neural network is proposed to coordinate and optimize multi-machine PSS and SVC additional damping controller in multi-operation mode. The embedded neural network separates the eigenvalue analysis of small disturbance in the process of optimization by the method of knowledge learning so as to improve the efficiency of optimization calculation of genetic algorithm. The effectiveness and superiority of the proposed method are also verified by simulations based on a four-machine two-area system and a large interconnected power network in a certain area. The input signal of SVC wideband additional damping controller is selected by calculating the principal modulus ratio index based on Prony analysis, and its parameters are optimized by an improved genetic algorithm based on embedded Adaboost-BP neural network. The subspace identification method is used to identify the reduced order of the system. Taking the four-machine two-region system as an example, a wide-area power system model with time delay is established. By using the stability criterion of time-delay systems based on free freedom matrix, the time-delay stability of wide-area systems with wide-area additional damping controllers is studied, and the time-delay stability margin of the systems is calculated.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM761.12;TM712

【相似文献】