Load frequency control strategies: A state-of-the-art survey for the researcher
TL;DR: In this paper, the authors provide an overview of control strategies for researchers, as well as of their current use in the field of load frequency control (LFC), and make various comparisons between these approaches, and the main advantages and disadvantages of the methods.
About: This article is published in Energy Conversion and Management.The article was published on 2009-02-01. It has received 504 citations till now. The article focuses on the topics: Electric power system & Wind power.
Citations
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TL;DR: In this article, a unified PID tuning method for load frequency control (LFC) of power systems is discussed, which is applicable to power systems with non-reheated, reheated, and hydro turbines.
Abstract: A unified PID tuning method for load frequency control (LFC) of power systems is discussed in this paper. The tuning method is based on the two-degree-of-freedom (TDF) internal model control (IMC) design method and a PID approximation procedure. The time-domain performance and robustness of the resulting PID controller is related to two tuning parameters, and robust tuning of the two parameters is discussed. The method is applicable to power systems with non-reheated, reheated, and hydro turbines. Simulation results show that it can indeed improve the damping of the power systems. It is shown that the method can also be used in decentralized PID tuning for multi-area power systems.
448 citations
Cites background from "Load frequency control strategies: ..."
...See [21] and [22] for a complete review of recent philosophies in AGC....
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TL;DR: This paper studies the load frequency control for power systems with communication delays via an event-triggered control method to reduce the amount of communications required and develops a new model of the LFC scheme with delays.
Abstract: This paper studies the load frequency control (LFC) for power systems with communication delays via an event-triggered control method to reduce the amount of communications required. The effect of the load disturbances on the augmented output is defined as a robust performance index of the augmented LFC scheme. By utilizing a time-delayed system design approach, a new model of the LFC scheme with delays is formulated, where the communication delays and event-triggered control are integrated for the LFC scheme. Based on the Lyapunov–Krasovskii functional method, the criteria for the event-triggered stability analysis and control synthesis of the LFC scheme are derived. Finally, the effectiveness of the proposed method is verified by simulation studies.
305 citations
Cites background from "Load frequency control strategies: ..."
...The load frequency control (LFC) has shown to be very effective in controlling power systems to supply sufficient and reliable electric power with guaranteed quality [2]....
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TL;DR: In this paper, a delay-dependent robust method is proposed for analysis/synthesis of a PID-type LFC scheme considering time delays, where the effect of the disturbance on the controlled output is defined as a robust performance index (RPI) of the closed-loop system.
Abstract: The usage of communication channels introduces time delays into load frequency control (LFC) schemes. Those delays may degrade dynamic performance, and even cause instability, of a closed-loop LFC scheme. In this paper, a delay-dependent robust method is proposed for analysis/synthesis of a PID-type LFC scheme considering time delays. The effect of the disturbance on the controlled output is defined as a robust performance index (RPI) of the closed-loop system. At first, for a preset delay upper bound, controller gains are determined by minimizing the RPI. Secondly, calculation of the RPIs of the closed-loop system under different delays provides a new way to assess robustness against delays and estimate delay margins. Case studies are based on three-area LFC schemes under traditional and deregulated environments, respectively. The results show that the PID-type controller obtained can guarantee the tolerance for delays less than the preset upper bound and provide a bigger delay margin than the existing controllers do. Moreover, its robustness against load variations and parameter uncertainties is verified via simulation studies.
270 citations
TL;DR: In this paper, a simple fuzzy-based frequency control method is proposed for the PV generator in a PV-diesel hybrid system without the smoothing of PV output power fluctuations.
Abstract: A photovoltaic (PV) system's output power fluctuates according to the weather conditions. Fluctuating PV power causes frequency deviations in the power utilities when the penetration is large. Usually, an energy storage system (ESS) is used to smooth the PV output power fluctuations and then the smoothed power is supplied to the utility. In this paper, a simple fuzzy-based frequency-control method is proposed for the PV generator in a PV-diesel hybrid system without the smoothing of PV output power fluctuations. By means of the proposed method, output power control of a PV generator considering the conditions of power utilities and the maximizing of energy capture are achieved. Here, fuzzy control is used to generate the PV output power command. This fuzzy control has average insolation, change of insolation, and frequency deviation as inputs. The proposed method is compared with a maximum power point tracking control-based method and with an ESS-based conventional control method. The numerical simulation results show that the proposed method is effective in providing frequency control and also delivers power near the maximum PV power level.
267 citations
Cites background from "Load frequency control strategies: ..."
...Some approaches considering frequency control have been reported in [25]–[30]....
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...A state of the art survey of load-frequencycontrol strategies could be found in [25]....
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TL;DR: In this paper, a simple approach to load frequency control (LFC) design for the power systems having parameter uncertainty and load disturbance is proposed, which is based on two-degree-of-freedom, internal model control (IMC) scheme, which unifies the concept of model-order reduction like Routh and Pade approximations.
Abstract: The large-scale power systems are liable to performance deterioration due to the presence of sudden small load perturbations, parameter uncertainties, structural variations, etc. Due to this, modern control aspects are extremely important in load frequency control (LFC) design of power systems. In this paper, the LFC problem is illustrated as a typical disturbance rejection as well as large-scale system control problem. For this purpose, simple approach to LFC design for the power systems having parameter uncertainty and load disturbance is proposed. The approach is based on two-degree-of-freedom, internal model control (IMC) scheme, which unifies the concept of model-order reduction like Routh and Pade approximations, and modified IMC filter design, recently developed by Liu and Gao [24]. The beauty of this paper is that in place of taking the full-order system for internal-model of IMC, a lower-order, i.e., second-order reduced system model, has been considered. This scheme achieves improved closed-loop system performance to counteract load disturbances. The proposed approach is simulated in MATLAB environment for a single-area power system consisting of single generating unit with a non-reheated turbine to highlight the efficiency and efficacy in terms of robustness and optimality.
258 citations
Cites background from "Load frequency control strategies: ..."
...The principle roles of LFC for power systems are: 1) maintaining zero steady state errors for frequency deviations, 2) counteracting sudden load disturbances, 3) minimizing unscheduled tie-line power flows between neighboring areas and transient variations in area frequency, 4) coping up with modeling uncertainties and system nonlinearities within a tolerable region, and 5) guaranteeing ability to perform well under prescribed overshoot and settling time in frequency and tie-line power deviations [1], [2]....
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References
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Book•
01 Jan 1994
TL;DR: In this article, the authors present a model for the power system stability problem in modern power systems based on Synchronous Machine Theory and Modelling, and a model representation of the synchronous machine representation in stability studies.
Abstract: Part I: Characteristics of Modern Power Systems. Introduction to the Power System Stability Problem. Part II: Synchronous Machine Theory and Modelling. Synchronous Machine Parameters. Synchronous Machine Representation in Stability Studies. AC Transmission. Power System Loads. Excitation in Stability Studies. Prime Mover and Energy Supply Systems. High-Voltage Direct-Current Transmission. Control of Active Power and Reactive Power. Part III: Small Signal Stability. Transient Stability. Voltage Stability. Subsynchronous Machine Representation in Stability Studies. AC Transmission. Power System Loads. Excitation in Stability Studies. Prime Mover and Energy Supply Systems, High-Voltage Direct-Current Transmission. Control of Active Power and Reactive Power. Part III: Small Signal Stability. Transient Stability. Voltage Stability. Subsynchronous Oscillations. Mid-Term and Long-Term Stability. Methods of Improving System Stability.
13,467 citations
Book•
04 Aug 1998
TL;DR: This is the first text in this area to fully integrate MATLAB and SIMULINK throughout and provides students with an author-developed POWER TOOLBOX DISK organized to perform analyses and explore power system design issues with ease.
Abstract: This text is intended for undergraduates studying power system analysis and design. It gives an introduction to fundamental concepts and modern topics with applications to real-world problems. This is the first text in this area to fully integrate MATLAB and SIMULINK throughout. It also provides students with an author-developed POWER TOOLBOX DISK organized to perform analyses and explore power system design issues with ease.
3,358 citations
TL;DR: In this paper, the authors present a critical literature review and an up-to-date and exhaustive bibliography on the AGC of power systems, highlighting various control aspects concerning the AGG problem.
Abstract: An attempt is made in This work to present critical literature review and an up-to-date and exhaustive bibliography on the AGC of power systems. Various control aspects concerning the AGC problem have been highlighted. AGC schemes based on parameters, such as linear and nonlinear power system models, classical and optimal control, and centralized, decentralized, and multilevel control, are discussed. AGC strategies based on digital, self-tuning control, adaptive, VSS systems, and intelligent/soft computing control have been included. Finally, the investigations on AGC systems incorporating BES/SMES, wind turbines, FACTS devices, and PV systems have also been discussed.
836 citations
804 citations