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M. A. Tammam,M. A. S. Aboelela,M. A. Moustafa,A. E. A. Seif
International Journal of Advances in Engineering and Technology , 2012,
Abstract: This paper studies control of load frequency in single and two area power systems with fuzzy like PID controller. In this study, multi-objective genetic algorithm is used to determine the parameters of the fuzzy like PID controller according to the system dynamics. The proposed controller has been compared with the conventional PID controllers tuned by Ziegler-Nicholasmethod and Particle Swarm Optimization technique. The overshoots and settling times with the proposed Genetic-PID controller are superior to the outputs of the same characteristics of the conventional PID controllers. The effectiveness of the proposed schemes is confirmed via extensive study using single area and two areas load frequency control examples through the application of MATLAB-Simulink software.
Optimal fractional-order PID controller design for interconnected power grid load frequency control considering time-delay

控制理论与应用 , 2017, DOI: 10.7641/CTA.2017.60959
Abstract: 分数阶PID控制器相比于传统整数阶PID控制器, 具有控制性能好、鲁棒性强等诸多优势, 可应用于电网的 负荷频率控制(load frequency control, LFC)中. 针对网络化时滞互联电网的LFC问题, 提出了一种基于计算智能的分 数阶PID控制器参数优化整定方案. 该方案选择时滞LFC系统时域输出响应构建优化目标函数, 采用最近提出的灰 狼优化算法获得最优的分数阶PID控制器参数, 所设计的控制器能确保一定时滞区间内LFC系统的稳定性. 仿真算 例表明, 所设计的LFC最优分数阶PID控制器比传统整数阶PID控制器的控制性能更优, 时滞鲁棒性更强.
Fractional-order PID controller, with the advantages of better performance and stronger robustness compared to traditional integer-order PID controller, can be applied to load frequency control (LFC) of interconnected power grid. A computational intelligence algorithm based parameter optimizing and tuning scheme of fractional-order PID controller is proposed in this paper for the complicated problems of networked time-delay interconnected power grid LFC. The timedomain output response of time-delay LFC system is modeled as an optimization objective function of the proposed scheme. The recently developed metaheuristic algorithm known as GreyWolf Optimizer algorithm is employed to iteratively identify the optimal parameters of fractional-order PID controller. The designed controller can guarantee the stability of the LFC system within a certain time-delay interval. The simulation results demonstrate that the designed optimal fractional-order PID controller has better control performance and stronger time-delay robustness than conventional integer-order PID controller.
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.
Modified Genetic Algorithm Based Load Frequency Controller for Interconnected Power Systems
S. Ramesh,A. Krishnan
International Journal of Electrical and Power Engineering , 2012,
Abstract: Power engineers have the responsibility to deliver economically, adequate and quality power to the consumers. In order to achieve this, the power system must be maintained at the desired operating level by suitable modern control strategies. The controlling of power system is becoming increasingly more complex due to large interconnections. The load frequency control is very important in power system operation and control for supplying sufficient and reliable electric power with good quality. This study deals with the application of real coded genetic algorithm for optimizing the gain of a proportional integral controller for load frequency control of interconnected power systems. Non-linearities such as Governor Dead Band (GDB) and Generation Rate Constraints (GRC) for a two-area reheat thermal power system have been included. Floating point representation has been used, since it is more consistent, more precise and leads to faster convergence. The simulation results confirm the designed control performance of the proposed controller.
C.Agees Kumar,N.Kesavan Nair
International Journal of Engineering Science and Technology , 2010,
Abstract: PID controller is widely used for main steam temperature control of boiler unit in thermal power plant. To avoid the drawback of current PID design methods, this paper presents a new design method for multi-objective PID controller to synthetically consider system requirement in reliability and robustness. Adaptive weighted PSO (AWPSO) technique is applied to the parameter optimization design. The optimization problem considered is highly nonlinear, complex, with multiple objectives and constraints. The simulation results on an actual main steam temperature control system indicate that, the multi-objective PID controller designed by presented method, can improve the dynamic performance of main steam temperature control system, with good robustness ability.
Genetic algorithm based PID controller design for a multi-area AGC scheme in a restructured power system
S Bhongade, B Tyagi, HO Gupta
International Journal of Engineering, Science and Technology , 2011,
Abstract: In this paper, a multi-area Automatic Generation Control (AGC) scheme suitable in a restructured interconnected power system has been proposed. Developed scheme utilizes a proportional, integral and derivative (PID) controller to control the output of the generators. The parameter of PID controller has been tuned according to Genetic Algorithm (GA) based performance indices. Developed model also include the Superconducting Magnetic Energy Storage (SMES) units to inject or absorb the active power of an interconnected power system. The functioning of Genetic Algorithm based PID controller has been tested on a 39-bus New England system and 75-bus Indian power system network. The results of GAPID controller have been compared with those obtained by using the Least Square Minimization method. Compliance with North American Electric Reliability Council (NERC) standards for AGC has also been established in this work.
Frequency Domain Design of Fractional Order PID Controller for AVR System Using Chaotic Multi-objective Optimization  [PDF]
Indranil Pan,Saptarshi Das
Mathematics , 2013, DOI: 10.1016/j.ijepes.2013.02.021
Abstract: A fractional order (FO) PID or FOPID controller is designed for an Automatic Voltage Regulator (AVR) system with the consideration of contradictory performance objectives. An improved evolutionary Non-dominated Sorting Genetic Algorithm (NSGA-II), augmented with a chaotic Henon map is used for the multi-objective optimization based design procedure. The Henon map as the random number generator outperforms the original NSGA-II algorithm and its Logistic map assisted version for obtaining a better design trade-off with an FOPID controller. The Pareto fronts showing the trade-offs between the different design objectives have also been shown for both the FOPID controller and the conventional PID controller to enunciate the relative merits and demerits of each. The design is done in frequency domain and hence stability and robustness of the design is automatically guaranteed unlike the other time domain optimization based controller design methods.
Load Frequency Control Using Optimal PID Controller for Non-Reheat Thermal Power System with Tcps Unit
V.Shanmugasundaram,A.R Rajkumar,T.Jayabarathi
International Journal of Engineering and Advanced Technology , 2012,
Abstract: The main objective of Load Frequency Control (LFC) is to regulate the power output of electric generator within an area, in response to the changes in system frequency and tie-line loading. Thus, LFC helps in maintaining the scheduled system frequency and tie-line power interchange with other areas within the prescribed limits. Most LFCs are primarily composed of an integral and PID controller. The integrator gain is set to a level that compromises between fast transient recovery and low overshoot in the dynamic response of the overall system. This type of controller is slow and does not allow the controller designer to consider the possible changes in operating condition and non-linearity in the generator unit. Moreover, it lacks in robustness. FACTS are designed to overcome the limitations of present non-reheat thermal-thermal power systems and enhance the power system stability. One of the promising FACTS devices is the Thyristor controlled phase shifter (TCPS) to alleviate this difficulty. TCPS is connected in the tie-line to self-tune the parameters of integral and PID controller. Two area system, have been considered for simulation of the proposed TCPS connected integral and PID controller .The performance of the Conventional controller, TCPS connected Integral and PID controller have beenCompared through MATLAB Simulation. The qualitative and quantitative comparisons have been carried out for Integral, PID controllers. The dynamic of performanceresponses of Integral and PID controller with TCPS shows that in terms of settling Time, peak overshoot and steady state error are greatly improved than that of without TCPS.
Load Frequency Control of Interconnected Hydro-Thermal System with Conventional Controllers and Expert Controllers  [cached]
Krishan Arora,Baljinder Singh
Buletin Teknik Elektro dan Informatika , 2012,
Abstract: Load-frequency control (LFC) is a part of the Automatic Generation Control (AGC) in power systems, the aim of which is to maintain the system frequency and tie line flow at their scheduled values during normal period in an interconnected system. This research paper is devoted to explore the interconnection of the load frequency control of hydro power system and the thermal system. The thermal system is comprised with governor dead band, generation rate constraint and boiler dynamics where as the hydro system is comprised with generation rate constraint. The conventional PID controller does not have adequate control performance with the consideration of nonlinearities and boiler dynamics. To overcome this drawback, Genetic Algorithm helps in solving optimization problems by exploitation of random search. The aim of the proposed expert controller is to restore the frequency to its nominal value in the smallest possible time whenever there is any change in the load demand etc.
Decentralized controller gain scheduling using PSO for power system restoration assessment in a two-area interconnected power system
R Jayanthi, IA Chidambaram, C Banusri
International Journal of Engineering, Science and Technology , 2011,
Abstract: Load Frequency Control (LFC) is one of the most important issues in electrical power system design/operation and is becoming much more significant recently with increasing size, changing structure and complexity in restoration of interconnected power systems. In practice, LFC systems are used with simple Proportional-Integral (PI) or Integral (I) controllers. However, since the PI or I control parameters are usually tuned based on classical or trial-and-error approaches, they are incapable of obtaining good dynamic performance if the power system is more vulnerable due to various load changing scenarios in multi-area power system. For this reason, in this study the P and I control parameters are tuned based on Particle Swarm Optimization (PSO) algorithm for a better Load-Frequency Control in a Two-Area Two-Unit Thermal Reheat Power System (TATURIPS) with step load perturbation. To exemplify the optimum parameter search PSO is used as it is an optimization method, therefore, even in the uncertainty area of controller parameters, finds the best parameters for controller and obtained controller is an optimal controller. This makes a trade-off between exploration and exploitation of search space to find global optimum in less number of generations. A TATURIPS is taken for the study to illustrate the proposed method. To show effectiveness of proposed method, the performance of optimized PI controller is obtained with several time-domain simulations for various load changes scenarios and is presented. Simulation results emphasis on the better settling time based stability performance of optimized PI controller in the TATURIPS with GT unit when compared with that of the SMES and the conventional system two-unit two-area interconnected power systems.
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