Robust Fuzzy Logic Control Strategies for Enhancing Power System Damping

ECS-9616631 Nehrir为了充分利用输电线路的传输能力，需要在电力系统控制方面取得重大进展，以抑制低频机电振荡。电力系统的稳定特性通常将输电线路上的最大允许功率传输限制在远低于线路热极限时的功率传输。电力系统的稳定特性取决于所采用的减振装置和减振控制策略。虽然有许多装置可用于电力系统以实现减振，但当前用于控制这些装置的策略通常不能提供足够的稳定性增强以使传输线能够在其热极限附近运行。为大电力系统开发更好的减振控制策略是本研究的重点。由于负荷变化的随机性和运行条件的时变性，很难对大型电力系统进行实时表征。模糊逻辑控制(FLC)是控制没有精确表征的系统的一种方法。模糊控制是目前备受关注的智能控制的一个分支。在电力系统领域，最近进行了几项关于在小电力系统中使用模糊逻辑控制的研究。在这项研究中，我们建议探索如何在电力系统控制装置中配置模糊控制器，如电力系统稳定器和静止无功补偿器，以抑制大规模电力系统的低频振荡。研究的第一阶段将包括一项基础性研究，以确定如何在多设备非线性动态系统中构建模糊控制器，以增加阻尼和增强稳定性和鲁棒性。本提案介绍了这方面的一些初步设计考虑。在第二阶段的研究中，将开发与电力系统控制装置结合使用的模糊控制器设计方法，以稳健地抑制大规模电力系统中的低频局部和区域间振荡。为了适应系统运行条件的广泛变化，将开发适用于大规模电力系统的替代设计策略，例如补充FLC和带有监督控制的FLC和自适应版本的模糊控制器。将使用先进的信号分析和识别算法来探索调整模糊控制器参数的方法。将使用几个模拟模型。最初，控制器设计方法和性能将在一个基本的三机九母线电力系统上进行评估。随后将对它们在更复杂系统上的使用进行基础性研究和评估，包括北美西部电力系统的降阶(17机、46母线)模型。这项拟议的研究是蒙大拿州立大学(MSU)电气工程系和新墨西哥大学(LTNM)的合作成果。牵头机构将是密歇根州立大学，在电力系统和控制方面拥有主要专业知识。新墨西哥大学将以模糊系统方面的主要专业知识参与这项工作(20%的工作)，并将探索在哪些条件下模糊逻辑控制可以保证具有多个振荡模式的大规模非线性动态系统的稳定性。这项工作将促进两所大学教职员工和研究生之间的合作努力。这项研究将促进电力系统减振和模糊逻辑控制的发展。它还将对研究生和本科生教育产生重大影响；研究生和本科生的直接参与已经计划好了。其中一项研究任务将涉及本科生参与在实验室规模的电力系统上实施FLC控制器。研究结果将在适当的会议上公布，并将在技术期刊上发表。

ECS-9616631 Nehrir In order to fully utilize the transmission capacity of transmission lines, significant advances need to be achieved in power system control as applied to the damping of low frequency electromechanical oscillations. Power system stability characteristics generally restrict the maximum allowable power transfers on transmission lines to be significantly below power transfers at thermal limits of the lines. The stability characteristics of power systems depend on damping devices and damping control strategies employed. While there are many devices that can be used in power systems to achieve damping, the strategies that are currently used to control these devices generally do not provide enough stability enhancement to enable operation of transmission lines near their thermal limits. The development of better damping control strategies for large power systems is the focus of this research. The characterization of large power systems in real time is difficult because of random load changes and time-varying operating conditions. One avenue to controlling systems that are not precisely characterized is fuzzy logic control (FLC). FLC is a branch of intelligent control that currently is receiving considerable attention. In the power systems area, several studies have been conducted recently on the use of FLC in small power systems. In this research, we propose to explore ways in which FLC can be configured with power system control devices such as power system stabilizers and static VAR compensators to dampen low-frequency oscillations in large-scale power systems. The first phase of the research will consist of a fundamental study to determine how FLC's can be structured in multiple-device nonlinear dynamic systems to increase damping and to enhance stability robustness. Some preliminary design considerations in this regard are described in this proposal. In the second phase of the research, methods of FLC design will be developed for use in conjunction with power system control devices for robust damping of low-frequency local and interarea oscillations in large-scale power systems. Alternative design strategies such as supplementary FLC and FLC with supervisory control and adaptive versions of fuzzy controllers suitable for application to large-scale power systems will be developed to account for wide variations in the system operating conditions. Methods of tuning fuzzy controller parameters will be explored using advanced signal analysis and identification algorithms. Several simulation models will be used. Initially, controller design methodologies and performance will be evaluated on a basic three-machine, nine-bus power system. This will be followed by a fundamental study and evaluation of their use on more complex systems, including a reduced-order (17-machine, 46-bus) model of the western North American power system. The proposed research is a collaborative effort between the Department of Electrical Engineering at Montana State University (MSU) and that at the University of New Mexico (LTNM). The lead institution will be MSU with primary expertise in power systems and control. The University of New Mexico will participate in the work (20% of the effort), with primary expertise in fuzzy systems, and will explore conditions under which fuzzy logic control can guarantee stability of large-scale nonlinear dynamic systems with multiple oscillatory modes. The work will foster collaborative efforts between faculty and graduate students at the two universities. The research should advance the state of the art both in power system damping and FLC. It will also have a big impact on graduate and undergraduate education; direct student involvement at both graduate and undergraduate levels has been planned. One of the research tasks will involve participation of undergraduate students in the implementation of FLC controllers on laboratory-scale power systems. Results of the research will be presented at appropriate conferences and will be pu blished in technical journals.