Suboptimal and near-optimal control of a load-frequency-control system

Moorthi, V.R.; Aggarwal, R.P.

doi:10.1049/piee.1972.0329

Cited by 26 publications

(10 citation statements)

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“…An observer for nonlinear systems is also presented in [200]. Due to the complexity and practical limitations of LFC in multi-area system, a suboptimal control strategy is investigated in [201][202][203]. To realize the decoupling of the interconnection into its subsystem components, model and singular perturbation techniques are employed [204].…”

Section: Optimal Control Methodsmentioning

confidence: 99%

“…To realize the decoupling of the interconnection into its subsystem components, model and singular perturbation techniques are employed [204]. Suboptimal and near-optimal controls are presented in [201] and a suboptimal AGC regulator scheme for a two-area interconnected system in [205,206]. Local controllers are employed for each subsystem to achieve decentralized controllers using local information to generate local control inputs by locating the closed loop poles of each controller in specified places on the complex plane.…”

Section: Optimal Control Methodsmentioning

confidence: 99%

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Challenges and Opportunities of Load Frequency Control in Conventional, Modern and Future Smart Power Systems: A Comprehensive Review

et al. 2018

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Power systems are the most complex systems that have been created by men in history. To operate such systems in a stable mode, several control loops are needed. Voltage frequency plays a vital role in power systems which need to be properly controlled. To this end, primary and secondary frequency control loops are used to control the frequency of the voltage in power systems. Secondary frequency control, which is called Load Frequency Control (LFC), is responsible for maintaining the frequency in a desirable level after a disturbance. Likewise, the power exchanges between different control areas are controlled by LFC approaches. In recent decades, many control approaches have been suggested for LFC in power systems. This paper presents a comprehensive literature survey on the topic of LFC. In this survey, the used LFC models for diverse configurations of power systems are firstly investigated and classified for both conventional and future smart power systems. Furthermore, the proposed control strategies for LFC are studied and categorized into different control groups. The paper concludes with highlighting the research gaps and presenting some new research directions in the field of LFC.Energies 2018, 11, 2497 2 of 35 before triggering the under/over frequency protection relays. The primary frequency control is usually implemented by the governor droop which results in steady stated errors. The secondary frequency control, which is called load frequency control (LFC) or automatic generation control (AGC), is responsible for regulating the frequency in power systems and has two main goals: (i) maintaining the frequency into a desirable range; and (ii) controlling the interchange power through major tie-lines between the different control areas. The main task of tertiary control level is re-dispatching generating units and ancillary reserve after a sever disturbance.With increasing the penetration level of renewable resources such as wind farms and photovoltaic plants in power systems, the uncertainties of active power production is highly increased, thus determining frequency variations. Such increase in active power fluctuation, beside the demand stochasticity, the frequency of power system would be highly oscillated. Therefore, future power systems need more robust and optimal LFC approaches that can handle such problems.Many control approaches have been suggested for LFC in interconnected power systems. These approaches can be categorized into four groups: (i) classical control approaches focus on designing proportional-integral-derivative (PID) controllers for controlling the frequency and tie-lines power flows; (ii) modern control approaches including optimal control method, sliding mode control schemes, and adaptive control systems; (iii) intelligent control schemes, such as fuzzy control systems; and (iv) soft computing-based approaches for controllers' parameter tuning which had a considerable attention from researchers in the last decade. Survey MethodologySeveral methodologies can be followed for conduc...

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Section: Optimal Control Methodsmentioning

confidence: 99%

Section: Optimal Control Methodsmentioning

confidence: 99%

Challenges and Opportunities of Load Frequency Control in Conventional, Modern and Future Smart Power Systems: A Comprehensive Review

et al. 2018

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“…Due to the technical limitations in the design of LFC using all state variables, sub-optimal LFC systems were introduced [68][69][70][71]. Apart from optimal/sub-optimal control strategies, the concept of variable-structure systems has also been used to design LFC regulators for power systems [72][73][74][75][76][77][78][79].…”

Section: A Literature Review On Lfc Synthesis/analysismentioning

confidence: 99%

Robust Power System Frequency Control

Bevrani

2009

838

541

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“…Most of such control techniques do not reflect the reality and become difficult to implement in a real power system. If the controller design is not robust against disturbance and parameters change, the system my become unstable [1,4].…”

Section: Introductionmentioning

confidence: 99%

Mixed H<sub>∞</sub>/H<sub>2</sub> with pole-placement design of robust LMI-based output feedback controllers for multi-area load frequency control

Bensenouci¹,

Ghany

2007

EUROCON 2007 - The International Conference on "Computer as a Tool"

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In this paper, mixed H ∞ /H 2 control theory with pole-placement is applied to design centralized and decentralized robust output feedback controllers for Load Frequency Control (LFC) of interconnected power systems. In the first stage, the original (full) system is taken as one block, i.e., centralized LFC system. In a second stage, it is decomposed into subsystems using the overlapping decentralization technique to obtain decentralized LFC system. Output feedback controllers are then designed, for both centralized and decentralized LFC, using the mixed H ∞ /H 2 that is solved using Linear Matrix Inequalities (LMI) technique. The role of H ∞ is to minimize the disturbance effect on the output represented by the area frequencies whereas H 2 is used to improve the transients in the tie-line powers. Pole-placement technique is used in conjunction with H ∞ and H 2 to place the system poles in a desired region. The separate effects of H ∞ , H 2 besides the mixed H ∞ /H 2 together with pole-placement on the system response are carried out for comparison purposes. The effects of the main design parameter of the mixed H ∞ /H 2 technique with shifted poles in the complex s-plane are investigated and the results are discussed. The system performance is analyzed through simulating severe disturbances and wide parameters variation in the presence on the system inherent nonlinearity. In both centralized and decentralized cases, the system with the designed robust controllers incorporated is found to fulfill the main LFC requirements.

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Suboptimal and near-optimal control of a load-frequency-control system

Cited by 26 publications

References 0 publications

Challenges and Opportunities of Load Frequency Control in Conventional, Modern and Future Smart Power Systems: A Comprehensive Review

Challenges and Opportunities of Load Frequency Control in Conventional, Modern and Future Smart Power Systems: A Comprehensive Review

Robust Power System Frequency Control

Mixed H<sub>∞</sub>/H<sub>2</sub> with pole-placement design of robust LMI-based output feedback controllers for multi-area load frequency control

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Suboptimal and near-optimal control of a load-frequency-control system

Cited by 26 publications

References 0 publications

Challenges and Opportunities of Load Frequency Control in Conventional, Modern and Future Smart Power Systems: A Comprehensive Review

Challenges and Opportunities of Load Frequency Control in Conventional, Modern and Future Smart Power Systems: A Comprehensive Review

Robust Power System Frequency Control

Mixed H<sub>&#x0221E;</sub>/H<sub>2</sub> with pole-placement design of robust LMI-based output feedback controllers for multi-area load frequency control

Contact Info

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Resources

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Mixed H<sub>∞</sub>/H<sub>2</sub> with pole-placement design of robust LMI-based output feedback controllers for multi-area load frequency control