UPFC的模糊调控控制研究

以统一潮流控制器（ＵＰＦＣ）为研究对象,针对共调制控制,引入模糊技术,设计了模糊调制顺,以抑制互联电力系统联络线功率振荡,改善系统的动态稳定性。给出了模糊调制控制器的结构,运用梯度下降法对模糊控制器的关键参数进行了优化。结合ＵＰＦＣ具有串、并联元件的特点,提出了模糊联合调制控制器,相对于单一元件调制控制,呵更有效地阻尼功率振荡。多机系统仿真结果表明模糊调控顺能有效地抑制振荡,并且在运行工况改变野性     

统一潮流控制器的模糊控制策略设计

本文建立了UPFC的动态数学模型,提出了UPFC的模糊控制策略。并对UPFC的四个调节器分别设计了控制器。文中对UPFC的阻尼控制器进行了改进,给出了运用带多个因子的模糊规则自调整的模糊控制器。并运用MATLAB的仿真工具,对含UPFC的双机系统进行了仿真。仿真结果表明,UPFC采用模糊控制后不但能有效地调节线路潮流,而且能有效地抑制振荡,提高电力系统的暂态稳定性。     

抑制区域间低频振荡的UPFC模糊滑模控制器

低频振荡是区域互联电力系统面对的重要问题。从暂态能量的角度对区域间低频振荡进行了分析,并以暂态能量函数下降为目标,分析了统一潮流控制器(UPFC)抑制区域间低频振荡的原理。进而设计了UPFC抑制区域间低频振荡的模糊滑模控制策略。该策略采用区域联络线电气量作为输入信号,构造滑模控制的切换函数,然后通过模糊控制器输出控制信号,改变UPFC串联侧输出电压,抑制低频振荡。该方法兼具滑模控制与模糊控制的优点,经四机两区域系统仿真分析,验证了所提抑制策略的有效性。     

统一潮流控制器的模糊控制策略设计

本文建立了UPFC的动态数学模型,提出了UPFC的模糊控制策略.并对UPFC的四个调节器分别设计了控制器.文中对UPFC的阻尼控制器进行了改进,给出了运用带多个因子的模糊规则自调整的模糊控制器.并运用MATLAB的仿真工具,对含UPFC的双机系统进行了仿真.仿真结果表明,UPFC采用模糊控制后不但能有效地调节线路潮流,而且能有效地抑制振荡,提高电力系统的暂态稳定性.     

基于遗传算法的UPFC模糊阻尼控制器参数优化及与梯度下降法的比较

设计了一种统一潮流控制器（UPFC）模糊辅助控制器,能够阻尼互联系统之间功率低频振荡．分别使用遗传算法和梯度下降法实现了模糊阻尼控制器（FDC）的参数优化。建立了UPFC的频域模型,给出了主控制和辅助控制的框图。推导了模糊阻尼控制器参数优化的公式。互联多机系统算例显示了2种优化方法都具有很好的收敛性。且结果吻合,同时由这2种方法优化的阻尼控制器能够很好地阻尼系统的功率振荡。且比传统的基于线性系统设计的辅助控制器在不同的系统运行方式和振荡模式下具有更好的鲁棒性。     

基于连续潮流法分析UPFC对电力系统潮流的控制

统一潮流控制器（UPFC）作为一种典型的FACTS装置,综合了FACTS元件的多种灵活控制手段。采用基于功率注入法的统一潮流控制器（UPFC）稳态模型,结合连续潮流法分析了UPFC在电力系统中的潮流控制特性。最后算例表明,UPFC可以控制线路的潮流分布,有效地提高电力系统的稳定性。     

统一潮流控制器的模糊控制器设计

建立并提出了UPFC的动态数学模型和模糊控制策略，并对其4个调节器分别设计了控制器。对UPFC的阻尼控制器进行了改进，给出了运用带多个因子的模糊规则自调整的模糊控制器。运用MATLAB的仿真工具，对含UPFC的双机系统进行了仿真。仿真结果表明，UPFC采用模糊控制后不但能有效地调节线路潮流，而且能有效抑制振荡，提高电力系统的动态稳定性。     

基于振荡能量下降原理的UPFC模糊控制器设计

研究了自适应统一潮流控制器(U PFC)模糊逻辑辅助阻尼控制器的设计方法。从振荡能量函数角度分析了U PFC安装线路的功率振荡特性,提出了以降低振荡能量为控制目标的阻尼控制策略。控制器以U PFC线路的功率为输入信号,通过对系统运行状态和控制效果进行评判,应用模糊规则自适应地调节控制参数,实现对系统功率振荡的有效抑制。控制器设计不需要系统的精确模型和参数。在10机新英格兰测试系统上的仿真研究表明,该控制器控制效果明显优于线性控制器,能有效抑制系统低频振荡,提高电力系统的动态稳定性水平,且具有较强的鲁棒性。     

统一潮流控制器(UPFC)对次同步振荡的影响及抑制策略

FACTS等快速控制装置在一定条件下可能激发电力系统的次同步振荡问题,导致发电机轴系失稳,造成重大事故,危害电力系统的安全稳定运行。UPFC作为一种新型FACTS元件,虽然能实现母线电压控制和线路有功、无功功率的调节,但对次同步振荡影响的研究较少。同时,目前的UPFC阻尼控制器多针对低频振荡模态。故在搭建UPFC模型的基础上,运用测试信号法,研究了系统运行参数和UPFC电压有功控制等对次同步振荡的影响,并设计了相应的UPFC附加阻尼控制器。在IEEE第二标准测试系统上的计算机仿真说明,该控制器能有效提高多个扭振模态的电气阻尼,抑制系统的次同步振荡。     

利用多端统一潮流控制器阻尼多模态振荡

研究了多机系统中使用统一潮流控制器(UPFC)抑制电力系统多模态振荡的可行性.首先推导了作为UPFC概念延伸的多端统一潮流控制器(MUPFC)的非线性动态模型和线性化的Phillips-Heffron模型.利用UPFC和MUPFC具有多个控制回路的特点,提出在其多个控制回路上附加多个阻尼控制器来阻尼多模态振荡.通过模态分析,采用可控性指标对系统中的各个弱阻尼模态选取有效的控制回路,并设计了附加阻尼控制器.仿真结果表明,通过该方法确定的在一个UPFC或MUPFC上设置的多个附加阻尼控制器能够成功实现对电力系统多模态振荡的抑制.     

Design of an ANN tuned adaptive UPFC supplementary damping controller for power system dynamic performance enhancement

A supplementary damping controller for a unified power flow controller (UPFC) is designed for power system dynamic performance enhancement. To maintain a good damping characteristic over a wide range of operating conditions, the gains of the UPFC supplementary damping controller are adapted in real time, based on online measured transmission line loadings (active and reactive power flows). To speed up the online gain adaptation process, an artificial neural network is designed. A major feature for the proposed adaptive UPFC supplementary damping controller is that only physically measurable variables (active and reactive power flows over the transmission line) are employed as inputs to the adaptive controller. To demonstrate the effectiveness of the proposed adaptive UPFC supplementary damping controller, computer simulations are performed on a power system subject to a three-phase fault. It is concluded from the simulation results that the proposed adaptive UPFC supplementary damping controller can yield satisfactory dynamic responses over a wide range conditions. The electromechanical mode with an oscillation frequency around 0.78 Hz has been effectively damped by the proposed damping compensators.     

Performance Evaluation of Power Oscillation Damping Controller—Firefly Algorithm Based Parameter Tuning

This paper presents the performance evaluation of power oscillation damping controller based on firefly algorithm (FA) parameter tuning. The power system stabilizer (PSS), unified power flow controller (UPFC), and static synchronous series compensator (SSSC) are tuned with FA by minimizing integral time multiplied by absolute error (ITAE) as an objective function. An integrated multi-stage linear quadratic regulator – power oscillation damping UPFC/SSSC has been proposed with precise tuning of control parameters which results in overall states' oscillation damping as compared to other classical methods. It has been observed that the proposed control structure damps the oscillations adequately and is modular in design methodology. The sample power system comprising six areas has been considered to demonstrate the effectiveness of the concept. The software has been developed based on the proposed work by the authors and the MATLAB code has been generated in R2009b version. The states' inter-relation which has been shown with eigenvalues reflects a better regulation and the step response is also validated.     

Comparison of different robust control methods in design of decentralized UPFC controllers

The unified power flow controller (UPFC) integrates properties of both shunt and series compensations, and can effectively alter power system parameters in such a way that increases power transfer capability and enhances system stability. In practice, simple proportional–integral (PI) controllers are used to control the UPFC. However, the PI control parameters are usually tuned based on classical or trial-and-error approaches and as such, they are incapable of obtaining good dynamic performance for a wide range of operating conditions and various loads in power systems. Hence, in this article robust control approaches are proposed based on the quantitative feedback theory (QFT), H_∞ loop-shaping and μ-synthesis, to design UPFC controllers (power-flow and DC-voltage regulator). The three mentioned methods are compared with each other and a supplementary damping controller is developed to improve damping power system oscillations. Here, a single-machine infinite-bus (SMIB) power system, installed with a UPFC (with system parametric uncertainties) is considered as a case study. The system parametric uncertainties are obtained following 40% simultaneous alterations in parameters and load from their typical values. The simulation results indicate satisfactory verifications of the robust control methods in dealing with the uncertainties considered. When the above three methods and the PI controller are compared in performance in several time-domain simulation tests, the results show clear superiority of the three methods over the PI controller, with the QFT presenting the best performance amongst the three robust control.     

Application of genetic algorithm in optimization of unified power flow controller parameters and its location in the power system network

This work demonstrates the application of Genetic Algorithm (GA) technique for the simultaneous stabilization of power systems using a Unified Power Flow Controller (UPFC). The GA is applied to find the optimal location of the UPFC and to tune its control parameters under different operating conditions. The problem is formulated as a multiobjective optimization problem which aims at maximizing the damping ratio of the electromechanical modes using different lines fitted with the UPFC. The approach is successfully tested on the 16-machine 68-bus New England–New York interconnected system and on the Iraqi National Super Grid System (INSGS) to validate its effectiveness in the damping of local and inter-area modes of oscillations. In addition, the proposed approach demonstrated better performance when compared to a fuzzy-based UPFC damping controller.     

阻尼振荡的GNF统一潮流控制器设计

在现代电力系统中,统一潮流控制器(UPFC)是调节电压和潮流的有效手段。该文提出一种用遗传算法优化参数的基于径向函数单一神经元的神经网络(RBFNN)和TS模糊控制策略综合而成的统一潮流控制器设计方案,TS模糊控制策略应用非线性规则设计了更为有效的控制器,使用RBFNN避免了产生控制器的训练样本,同时利用GA全局优化TS模糊控制的参数,从而提高系统的暂态稳定性。经验证,该方案比传统的PI控制策略具有更好的系统振荡阻尼性能。     

统一潮流控制器附加阻尼抑制次同步谐振的理论与仿真

随着串联电容补偿输电的推广应用,中国电力系统面临着严峻的次同步谐振(SSR)问题。针对SSR问题,文中基于采用电流控制模式的统一潮流控制器(UPFC),提出了一种UPFC附加阻尼控制抑制SSR的方法;首先选择了附加阻尼控制信号接入UPFC控制器的位置,然后设计了UPFC附加次同步阻尼控制器(SSDC),并推导了其抑制系统SSR的机理,且所设计的SSDC采用了模态分离控制以达到抑制多模态SSR的目的。最后,综合利用复转矩系数和时域仿真的方法,对所设计的UPFC装置SSDC抑制SSR的有效性进行了分析和仿真。结果表明,所设计的SSDC在有效抑制SSR的同时,不会影响系统和UPFC装置的正常运行。     

基于PSCAD/EMTDC的统一潮流控制器动态仿真模型

设计了组成统一潮流控制器(UPFC)的动态仿真模型的各个模块,包括正弦脉宽调制(SPWM)信号产生模块、电压源变换器(VSC)控制模块和UPFC控制器的比例积分(PI)控制电路.首先采用三相桥式全控电路组成VSC,VSC的开关器件采用绝缘栅双极性晶体管(IGBT),门极信号按SPWM的方式产生.然后通过分析线路传输功率方程设计了一个简单的PI控制器,并构成完整的UPFC仿真模型.还基于该动态模型对UPFC在功率调节、电压控制和抑制振荡等方面的功能进行了仿真分析.仿真结果表明该UPFC仿真模型在线路功率发生较大变动时能使线路快速恢复;在系统发生三相短路时能有效减少系统的功率损失和减小母线电压的暂降幅度;在系统发生功率波动时还能大幅度减小振幅.     

UPFC改善含风电电力系统阻尼特性分析

风力发电并网容量的提高对电力系统阻尼特性的影响越来越明显,需研究相关措施来改善风电并网后系统阻尼特性。构建了含统一潮流控制器UPFC(Unified Power Flow Controller)的风电并网系统数学模型,设计了UPFC附加功率振荡阻尼控制器,以IEEE 2区域4机系统为例,从特征根分析和动态时域仿真两方面系统地分析了所提UPFC对含风电电力系统阻尼特性的改善效果。研究结果表明,所设计的UPFC增强了含风电电力系统的阻尼效果,使互联系统在高联络线传输功率下仍可稳定运行。