scholarly journals Optimal Decentralized LQR Control to Enhance Multi-Area LFC System Stability

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Ashraf M. Abdelhamid ◽  
Ahmed A. M. El-Gaafary
Keyword(s):  
Power System ◽  
Frequency Control ◽  
Linear Quadratic Regulator ◽  
Load Frequency Control ◽  
System Stability ◽  
Linear Quadratic ◽  
Single Input Single Output ◽  
Load Frequency ◽  
Single Output ◽  
Optimal Linear

Many studies have been made in the field of load frequency control (LFC) through the last few decades because of its importance to healthy power system. It is important to maintain frequency deviation at zero level after a load perturbation. In decentralized control, the multi-area power system is decomposed into many single input single output (SISO) subsystems and a local controller is designed for each subsystem. The controlled subsystems may have slow poles; these undesired poles may drive the aggregated overall system into the instability region. Thus, it is required to relocate these poles to much more stable places to avoid their effect upon the overall system stability. This study aims to design a new load frequency controller based on the powerful optimal linear quadratic regulator (LQR) technique. This technique can be applied over subsystem level to shift each subsystem undesired poles one by one into a prespecified stable location which in turn shift the overall system slow poles and reduce the effect of the interaction between the interconnected subsystems among each other. This procedure must be applied many times as the number of undesired poles (pairs) until all the desired poles are achieved. The main objective is considered to get a robust design when the system is affected by a physical disturbance and ±40% model uncertainties. LQR can be applied again over the aggregated system to enhance the stability degree. Simulation results are used to evaluate the effectiveness of the proposed method and compared to other research results.

scholarly journals Load frequency control of a hydro dominating interconnected power system

2020 ◽  
Author(s):  
◽  
Milan Joshi
Keyword(s):  
Power System ◽  
Closed Loop ◽  
Frequency Control ◽  
Linear Quadratic Regulator ◽  
Load Frequency Control ◽  
Accurate Estimation ◽  
Renewable Energy Resources ◽  
Linear Quadratic ◽  
Random Load ◽  
Load Frequency

Energy is one of the vital figures that impact the development of civilization in the 21st century. It has been projected that by the year 2050, global energy needs will be satisfied by renewable sources. Among these renewable energy resources hydropower is available worldwide with relatively cheaper accessibility for most of the communities. Nevertheless, hydropower's control architecture raises concern for the system operators in terms of preserving the Load Frequency Control (LFC) services due to the elongated response time of hydro turbines in catering for the varying load demands. The varying load demands are inevitable in the power system due to different clients’ energy consumption patterns at different times. This, therefore, places changing control framework requests as per the requirement of diverse clients. Hence, the research proposes and demonstrates the connection of the hydro-hydro framework through the AC tie- line for LFC. The Linear Quadratic Regulator (LQR) is a plan for hydro overseeing framework in discrete mode. The application derived is displayed through closed- loop feedback gains and closed-loop eigenvalues. In the expansion model, the positive effect of a Unified Power Flow Controller (UPFC) and Redox Flow Battery (RFB) in LFC studies is investigated. This proposition moreover shows the joint endeavors of Fuzzy Logic (FL) as well as Proportional Integral Derivative (PID), with control gains well-calculated, through Particle Swarm Optimization (PSO) result into a robust FL-PSO-PID for LFC of the connected hydro framework. The different errors are defined to assess the yield as well as the execution of the FL-PSO-PID. The yield appears through a decline in blunder values as well as minimization in framework responses from accurate estimation for the LFC under various working conditions such as non- linearity, random load alteration, and parametric move as a result of a precise estimate. In the expansion, the effect of energy storage devices is also investigated to understand the enhancement provided frequency control of the hydro system, and the result obtained shows their effectiveness. Finally, the outcomes and future extent of this investigation work have been presented.

scholarly journals Distributed LQR Design for a Class of Large-Scale Multi-Area Power Systems

Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2664 ◽  
Author(s):  
Eleftherios Vlahakis ◽  
Leonidas Dritsas ◽  
George Halikias
Keyword(s):  
Power Systems ◽  
Power System ◽  
Large Scale ◽  
Convex Combination ◽  
Frequency Control ◽  
Linear Quadratic Regulator ◽  
Load Frequency Control ◽  
Linear Quadratic ◽  
Load Frequency ◽  
Power Load

Load frequency control (LFC) is one of the most challenging problems in multi-area power systems. In this paper, we consider power system formed of distinct control areas with identical dynamics which are interconnected via weak tie-lines. We then formulate a disturbance rejection problem of power-load step variations for the interconnected network system. We follow a top-down method to approximate a centralized linear quadratic regulator (LQR) optimal controller by a distributed scheme. Overall network stability is guaranteed via a stability test applied to a convex combination of Hurwitz matrices, the validity of which leads to stable network operation for a class of network topologies. The efficiency of the proposed distributed load frequency controller is illustrated via simulation studies involving a six-area power system and three interconnection schemes. In the study, apart from the nominal parameters, significant parametric variations have been considered in each area. The obtained results suggest that the proposed approach can be extended to the non-identical case.

scholarly journals Review on load frequency control for power system stability

2021 ◽  
Vol 19 (2) ◽  
pp. 638
Author(s):  
Muhammad Nizam Kamarudin ◽  
Nabilah Shaharudin ◽  
Noor Haqkimi Abd Rahman ◽  
Mohd Hendra Hairi ◽  
Sahazati Md. Rozali ◽  
...  
Keyword(s):  
Power System ◽  
Frequency Control ◽  
Power System Stability ◽  
Load Frequency Control ◽  
System Stability ◽  
Load Frequency

scholarly journals Gravitational Search Algorithm Based Automatic Load Frequency Control for Multi-Area Interconnected Power System

2021 ◽  
Vol 12 (3) ◽  
pp. 4548-4568
Author(s):  
Samuel Jonas Yeboah Et.al
Keyword(s):  
Power System ◽  
Pid Controller ◽  
Search Algorithm ◽  
Frequency Control ◽  
Gravitational Search Algorithm ◽  
Load Frequency Control ◽  
System Stability ◽  
Interconnected Power System ◽  
Load Frequency ◽  
Gravitational Search

Demand and frequency deviation is gaining more popularity in power system research especially with multiple power systems interconnections and operations as a result of the complexity of power system network, network upgrade and renewable energy sources integration. However, stability of the power system with respect to momentarily fault of Load Frequency Control (LFC) models, in terms of time taken for the fault to settle, magnitude of overshoot and Steady-State Error (SSE) margin, still remain a challenge to the various proposed LFC designs for power system stability. This paper proposes an intelligent demand and frequency variations controller for a four-area interconnected power system using Gravitational Search Algorithm (GSA) optimisation technique. Proportional Integral Derivative (PID) controller and Gravitational Search Algorithm (GSA) were integrated and implemented on the interconnected power system. The optimised GSA-PID controller demonstrated robustness and superiority with time taken for the instability to settle and maximum overshoot in all the four areas as compared to results with Particle Swarm Optimisation (PSO) PID controller and conventional PID controller under 1% and 5% load perturbation. The settling time in all the areas produced tremendous results with GSA-PID controller compared to the results of PSO-PID and conventional PID, the performance of GSA-PID controller shows better dynamic responses with superior damping, less overshoot, minimum oscillations and shorter transient duration.

scholarly journals Impact of communication delay on distributed load frequency control (dis-LFC) in multi-area power system (MAPS)

2019 ◽  
Vol 15 (4) ◽  
pp. 626-632 ◽  
Author(s):  
Auwal Mustapha Imam ◽  
Kashif Chaudhary ◽  
Abdullahi Bala Kunya ◽  
Zuhaib Rizvi ◽  
Jalil Ali
Keyword(s):  
Power System ◽  
Large Scale ◽  
Frequency Control ◽  
Load Frequency Control ◽  
Communication Delay ◽  
System Stability ◽  
Worst Case ◽  
Load Frequency ◽  
Distributed Load ◽  
The Impact

AIn this paper, impact of communication delay on distributed load frequency control (dis-LFC) of multi-area interconnected power system (MAIPS) is investigated. Load frequency control (LFC), as one of ancillary services, is aimed at maintaining system frequency and inter-area tie-line power close to the scheduled values, by load reference set-point manipulation and consideration of the system constraints. Centralized LFC (cen-LFC) requires inherent communication bandwidth limitations, stability and computational complexity, as such, it is not a good technique for the control of large-scale and geographically wide power systems. To decrease the system dimensionality and increase performance efficiency, distributed and decentralized control techniques are adopted. In distributed LFC (dis-LFC) of MAIPS, each control area (CA) is equipped with a local controller and are made to exchange their control actions by communication with controllers in the neighboring areas. The delay in this communication can affect the performance of the LFC scheme and in a worst case deteriorates power system stability. To investigate the impact of this delay, model predictive controller (MPC) is employed in the presence of constraints and external disturbances to serve as LFC tracking control. The scheme discretizes the system and solves an on-line optimization at each time sample. The system is subjected to communication delay between the CAs, and the response to the step load perturbation with and without the delay. Time-based simulations were used on a three-area MAIPS in MATLAB/SIMULINK environment to verify the investigations. The overshoot and settling time in the results reveals deterioration of the control performance with delay.  Also, the dis-LFC led to zero steady states errors for frequency deviations and enhanced the MAIPS’ performance. With this achievement, MPC proved its constraints handling capability, online rolling optimization and ability to predict future behavior of systems.

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