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Automatic Generation Control for Interconnected Hydro-thermal System with the help of Conventional Controllers
Vikram Kumar Kamboj,Krishan Arora,Preeti Khurana
International Journal of Electrical and Computer Engineering , 2012, DOI: 10.11591/ijece.v2i4.305
Abstract: The Problem of Automatic Generation Control of large interconnected multi-area system is necessitated by the importance of maintenance of frequency and tie-line flows at their scheduled values. Disturbance in any part of the power system network has its effect on the frequency and tie-line power flows of the entire network. Thus, It is the responsibility of the Power system engineers to ensure that adequate power is delivered to the load reliably and economically so that nominal condition will be re-established. This Research paper aims to represents how nominal value can be achieved by close loop control of real and reactive powers generated in the controllable source of the system with the help of conventional controllers.
Load frequency control of three area interconnected hydro-thermal reheat power system using artificial intelligence and PI controllers
S Prakash, SK Sinha
International Journal of Engineering, Science and Technology , 2012,
Abstract: This paper present analysis on dynamic performance of Load Frequency Control (LFC) of three area interconnected hydrothermal reheat power system by the use of Artificial Intelligent and PI Controller. In the proposed scheme, control methodology developed using conventional PI controller, Artificial Neural Network (ANN) and Fuzzy Logic controller (FLC) for three area interconnected hydro-thermal reheat power system. In this paper area-1 and area-2 consists of thermal reheat power plant whereas area-3 consists of hydro power plant. In this proposed scheme, the combination of most complicated system like hydro plant and thermal plant with reheat turbine are interconnected which increases the nonlinearity of the system. The performances of the controllers are simulated using MATLAB/SIMULINK package. A comparison of PI controller, Fuzzy controller and ANN controller based approaches shows the superiority of proposed ANN based approach over Fuzzy and PI for same conditions. To enhance the performance of PI, Fuzzy and neural controller sliding surface is included. The simulation results also tabulated as a comparative performance in view of settling time and peak over shoot.
performance evaluation of evolutionary designed conventional AGC controllers for interconnected electric power system studies in a deregulated market environment
Y Karnavas, K Dedousis
International Journal of Engineering, Science and Technology , 2010,
Abstract: Electric power industry is currently in transition from vertically integrated utilities to an industry that will incorporate competitive companies. This increases the complexity of the load frequency issue and calls for more insight and research. In this context, the tuning of a multi-area automatic generation control (AGC) system after deregulation and furthermore, the effect of reheat turbines dynamics in the power system performance, are not yet discussed in depth and are studied in this work. The effect of bilateral contracts on the dynamics of the system is taken into account and the concept of DISCO participation matrix for these bilateral contracts is simulated. Genetic algorithms are adopted in order to obtain the optimal parameters of the load-frequency controllers as well as of the frequency biases of thermal systems with reheat turbines. Also, since the optimum parameter values of the classical AGC have been obtained in the literature by minimizing the popular integral of the squared errors criterion (ISE) only, an effort is made in this study to show that this criterion does not give always the best system performance especially in a deregulated environment. In this work, we investigate the optimum adjustment of the load frequency controllers using a set of performance indices which are various functions of error and time. In this way, someone can observe the various performances that such a kind of power system might have when a different performance index is used. It should be noted that to the extent of the authors' knowledge, this kind of optimization has not been done yet in the literature. The performances of the tuned two–area AGC system are obtained using appropriate Matlab/Simulink models. Finally, it is envisaged that the synthesis procedure highlighted in this paper could be of practical significance for tuning conventional AGC controllers for an interconnected thermal-electric power system in a deregulated environment.
Application of artificial intelligence in load frequency control of interconnected power system
S Prakash, SK Sinha
International Journal of Engineering, Science and Technology , 2011,
Abstract: This paper presents the use of artificial intelligence to study the load frequency control of interconnected power system. In the proposed scheme, a control methodology is developed using Artificial Neural Network (ANN) and Fuzzy Logic controller (FLC) for interconnected hydro-thermal power system. The control strategies guarantees that the steady state error of frequencies and inadvertent interchange of tie-lines power are maintained in a given tolerance limitations. The performances of the controllers are simulated using MATLAB/SIMULINK package. A comparison of Fuzzy controller and ANN controller based approaches shows the superiority of proposed ANN based approach over Fuzzy one for different loading conditions (1% and 2% step load variations). The simulation results also tabulated as a comparative performance in view of settling time and peak over shoot.
An Investigation of ANN based PID Controllers using Three- Area Load Frequency Control in Interconnected Power System
V.Shanmuga Sundaram ,,Dr. T.Jayabharathi
International Journal of Engineering Science and Technology , 2011,
Abstract: The LFC problem, which is the major requirement in parallel operation of several interconnected systems, is one of very important subjects in power system studies. In this study, the power systems with threeareas connected through tie-lines are considered. The perturbation of frequencies at the areas and resulting tieline power flows arise due to unpredictable load variations that cause mismatch between the generated and demanded powers. The objective of LFC is to minimize the transient deviations and to provide zero steady state errors of these variables in a very short time. Variation in load frequency is an index for normal operation of power systems. When load Perturbation takes place anywhere in any area of the system, it will affect the frequency at other areas also. To control load frequency of power systems various controllers are used in different areas, but due to non-linearity's in the system components and alternators, these controllers cannot control the frequency quickly and efficiently. The simple neural networks can alleviate this difficulty. This paper deals with various controllers like proportional integral (PI), Proportional Integral Derivative (PID) andANN (Artificial neural network) tuned PID controller for three area load frequency control.The performance of the PID type controller with fixed gain, Conventional integral controller (PI) and ANN based PID (ANN-PID) controller have been compared through MATLAB Simulation results. Comparison of performance responses of integral controller & PID controller show that the ANN- PID controller has quite satisfactory generalization capability, feasibility and reliability, as well as accuracy in three area system. The qualitative and quantitative comparison have been carried out for Integral,PID and ANN- PID controllers. The superiority of the performance of ANN over integral and PID controller is highlighted.
Synthesis of Decentralized Variable Gain Robust Controllers for Large-Scale Interconnected Systems with Structured Uncertainties  [PDF]
Shunya Nagai,Hidetoshi Oya
Journal of Control Science and Engineering , 2014, DOI: 10.1155/2014/848465
Abstract: In this paper, we propose a decentralized variable gain robust controller which achieves not only robust stability but also satisfactory transient behavior for a class of uncertain large-scale interconnected systems. For the uncertain large-scale interconnected system, the uncertainties and the interactions satisfy the matching condition. The proposed decentralized robust controller consists of a fixed feedback gain controller and a variable gain one determined by a parameter adjustment law. In this paper, we show that sufficient conditions for the existence of the proposed decentralized variable gain robust controller are given in terms of LMIs. Finally, a simple numerical example is included. 1. Introduction To design control systems, it is necessary to derive a mathematical model for controlled systems. However, there always exist some gaps between the mathematical model and the controlled system; that is, uncertainties between actual systems and mathematical models are unavoidable. Hence for dynamical systems with uncertainties, so-called robust controller design methods have been well studied in the past thirty years, and there are a large number of studies for linear uncertain dynamical systems (e.g., see [1, 2] and references therein). In particular for uncertain linear systems, several quadratic stabilizing controllers and one have been suggested (e.g., [3–5]), and a connection between control and quadratic stabilization has also been established [6]. In addition, several design methods of variable gain controllers for uncertain continuous-time systems have been shown (e.g., [7–9]). These robust controllers are composed of a fixed gain controller and a variable gain one, and variable gain controllers are tuned by updating laws. Especially, in Oya and Hagino [8] the error signal between the desired trajectory and the actual response is introduced and the variable gain controller is determined so as to reduce the effect of uncertainties. On the other hand, the decentralized control for large-scale interconnected systems has been widely studied, because large-scale interconnected systems can be seen in such diverse fields as economic systems, electrical systems, and so on. A large number of results in decentralized control systems can be seen in ?iljak [10]. A framework for the design of decentralized robust model reference adaptive control for interconnected time-delay systems has been considered in the work of Hua et al. [11] and decentralized fault tolerant control problem has also been studied [12]. Additionally, there are many existing results
IMPROVEMENT OF DYNAMIC PERFORMANCE OF THREE AREA HYDRO-THERMAL SYSTEM INTERCONNECTED WITH AC-TIE LINE PARALLEL WITH HVDC LINK IN DEREGULATED ENVIRONMENT
L. ShanmukhaRao,N. Venkata Ramana
International Journal of Advances in Engineering and Technology , 2012,
Abstract: This paper presents analysis on Improvement of dynamic performance of a three-area Hydro-thermal system interconnected with AC tie-line parallel with HVDC link when subjected to parametric uncertainties when compared to a three-area Hydro-thermal system interconnected with AC tie-line. In this paper three areas consists of one Hydro and one thermal power plant are considered.AC-Tie line parallel with HVDC link is used as a system interconnection between all the three areas. Open transmission access and the evolution of more socialized companies for generation, transmission and distribution affects the formulation of Automatic Generation Control (AGC) problem. So, the traditional three area system is modified and taken into the account the effect of bilateral contracts on the dynamics.
What Results from Applying Conventional Controllers to MATLAB Neural Network Demos
Ryszard Gessing
Theoretical and Applied Informatics , 2010, DOI: 10.2478/v10179-010-0016-y
Abstract: It is shown that appropriate conventional controllers applied to strongly nonlinear plants taken from MATLAB Neural Network (NN) Control Systems Demos are significantly better than NN controllers appearing in these Demos. Moreover the conventional controllers operate well for significantly larger changes of the reference signal without the need of their re-tuning. The applied conventional controllers fulfill the demands of formulated in the present paper the Criterion RD1 (Relative Degree =1).
Comparison between Conventional and Fuzzy Logic PID Controllers for Controlling DC Motors  [PDF]
Essam Natsheh,Khalid A. Buragga
International Journal of Computer Science Issues , 2010,
Abstract: Fuzzy logic and proportional-integral-derivative (PID) controllers are compared for use in direct current (DC) motors positioning system. A simulation study of the PID position controller for the armature-controlled with fixed field and field controlled with fixed armature current DC motors is performed. Fuzzy rules and the inferencing mechanism of the fuzzy logic controller (FLC) are evaluated by using conventional rule-lookup tables that encode the control knowledge in a rules form. The performance assessment of the studied position controllers is based on transient response and error integral criteria. The results obtained from the FLC are not only superior in the rise time, speed fluctuations, and percent overshoot but also much better in the controller output signal structure, which is much remarkable in terms of the hardware implementation.
Automatic generation control of interconnected power system with diverse sources of power generation
K.S.S Ramakrishna, P Sharma, T Bhatti
International Journal of Engineering, Science and Technology , 2010,
Abstract: In this paper, automatic generation control (AGC) of two area interconnected power system having diverse sources of power generation is studied. A two area power system comprises power generations from hydro, thermal and gas sources in area-1 and power generations from hydro and thermal sources in area-2. All the power generation units from different sources are equipped with speed governors. A continuous time transfer function model of the system for studying dynamic response for small load disturbances is presented. A proportional-integral-derivative (PID) automatic generation control scheme is applied only to power generations from thermal and gas sources and power generation from hydro source is allowed to operate at its scheduled level with only speed governor control. The two area power system is simulated for different nominal loading conditions. Genetic algorithm (GA) is used to obtain the optimal PID gains for various cases using integral squared error plus integral time absolute error (ISE+ITAE) performance index for fitness evaluation. Some of the transient responses are shown for different nominal loading conditions due to step load disturbances in the system.
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