scholarly journals Effect of different Communication Delay Latencies on LMI based Load Frequency Control Model

2019 ◽  
Vol 8 (11) ◽  
pp. 2325-2329
Keyword(s):  
Power System ◽  
Time Delays ◽  
Frequency Control ◽  
Load Frequency Control ◽  
Communication Delay ◽  
Linear Matrix ◽  
Nonlinear Parameters ◽  
Adverse Conditions ◽  
Load Frequency ◽  
The Stability

This paper present’s the study of Load Frequency Control (LFC) with certain nonlinear parameters at different communication delay latencies. The main aim is to maintain the stability of power system in all the adverse conditions including time delays in the network. Here, the stability of the system is demonstrated using Lyapuonav stability theorem in the presence of Delay’s and Linear Matrix Inequalities (LMI). Time delays are taken in the network. These delay latencies are linearized using the rational approximation method. Here Padé approximation is used with different time delay values. The problem is formulated using a decentralized LFC approach for a power system containing a single area. Simulation results carried out with different delay latency values integrated with the Load frequency control LMI and rigorous analysis is performed to test the robustness of the proposed strategy

scholarly journals Secure Load Frequency Control of Smart Grids under Deception Attack: A Piecewise Delay Approach

Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2266 ◽  
Author(s):  
Fei Zhao ◽  
Jinsha Yuan ◽  
Ning Wang ◽  
Zhang Zhang ◽  
Helong Wen
Keyword(s):  
Smart Grids ◽  
Controller Design ◽  
Design Method ◽  
Frequency Control ◽  
Functional Method ◽  
Load Frequency Control ◽  
Linear Matrix ◽  
Load Frequency ◽  
The Stability

The problem of secure load frequency control of smart grids is investigated in this paper. The networked data transmission within the smart grid is corrupted by stochastic deception attacks. First, a unified Load frequency control model is constructed to account for both network-induced effects and deception attacks. Second, with the Lyapunov functional method, a piecewise delay analysis is conducted to study the stability of the established model, which is of less conservativeness. Third, based on the stability analysis, a controller design method is provided in terms of linear matrix inequalities. Finally, a case study is carried out to demonstrate the derived results.

scholarly journals Robust LFC Strategy for Wind Integrated Time-Delay Power System Using EID Compensation

Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3223 ◽  
Author(s):  
Liu ◽  
Zhang ◽  
Zou
Keyword(s):  
Time Delay ◽  
Power System ◽  
Closed Loop ◽  
Frequency Control ◽  
Loop System ◽  
Load Frequency Control ◽  
System Stability ◽  
Linear Matrix ◽  
Closed Loop System ◽  
The Stability

This paper presents an active disturbance rejection control (ADRC) technique for load frequency control of a wind integrated power system when communication delays are considered. To improve the stability of frequency control, equivalent input disturbances (EID) compensation is used to eliminate the influence of the load variation. In wind integrated power systems, two area controllers are designed to guarantee the stability of the overall closed-loop system. First, a simplified frequency response model of the wind integrated time-delay power system was established. Then the state-space model of the closed-loop system was built by employing state observers. The system stability conditions and controller parameters can be solved by some linear matrix inequalities (LMIs) forms. Finally, the case studies were tested using MATLAB/SIMULINK software and the simulation results show its robustness and effectiveness to maintain power-system stability.

scholarly journals Robust Distributed Model Predictive Load Frequency Control of Interconnected Power System

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Xiangjie Liu ◽  
Huiyun Nong ◽  
Ke Xi ◽  
Xiuming Yao
Keyword(s):  
Power System ◽  
Large Scale ◽  
Frequency Control ◽  
Load Frequency Control ◽  
Distributed Model ◽  
Linear Matrix ◽  
Interconnected Power System ◽  
Load Frequency ◽  
Distributed Model Predictive Control ◽  
System A

Considering the load frequency control (LFC) of large-scale power system, a robust distributed model predictive control (RDMPC) is presented. The system uncertainty according to power system parameter variation alone with the generation rate constraints (GRC) is included in the synthesis procedure. The entire power system is composed of several control areas, and the problem is formulated as convex optimization problem with linear matrix inequalities (LMI) that can be solved efficiently. It minimizes an upper bound on a robust performance objective for each subsystem. Simulation results show good dynamic response and robustness in the presence of power system dynamic uncertainties.

scholarly journals An Improved Stability Criterion for Load Frequency Control of Power Systems with Time-Varying Delays

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 2101
Author(s):  
Bi-Ying Chen ◽  
Xing-Chen Shangguan ◽  
Li Jin ◽  
Dan-Yun Li
Keyword(s):  
Power Systems ◽  
Stability Criterion ◽  
Frequency Control ◽  
Load Frequency Control ◽  
Linear Matrix ◽  
Time Varying ◽  
Time Varying Delay ◽  
Load Frequency ◽  
Improved Stability ◽  
The Stability

This paper aims at developing a novel stability criterion to access the influence of the time-varying delay on the stability of power systems equipped with a proportional-integral (PI)-based load frequency control (LFC). The model of the LFC scheme considering time-varying communication delays is established at first. Then, an improved stability condition related to the information of delay bounds is deduced by constructing an augmented Lyapunov–Krasovski functional and using a matrix inequality, and it is expressed as linear matrix inequalities (LMIs) for easily checking. Finally, case studies for one-area and two-area LFC systems are carried out to show the relationship between delay margins ensuring the stability and the PI gains of the LFC, and also verify the superiority of proposed stability criterion compared with the previous ones.

Design of Specification Oriented Compensator with a PID Controller for Load Frequency Control

2014 ◽  
Vol 573 ◽  
pp. 248-253
Author(s):  
Soundarapandian Anbarasi ◽  
Srinivasan Muralidharan
Keyword(s):  
Power System ◽  
Pid Controller ◽  
Frequency Control ◽  
Thermal Power ◽  
Absolute Error ◽  
Load Frequency Control ◽  
Integration Time ◽  
Load Frequency ◽  
Thermal Power System ◽  
The Stability

This paper proposes a design of Specification Oriented Compensator (SOC) with a Proportional Integral Derivative (PID) controller for Load frequency Control (LFC) in a thermal power system. The phase margin which is derived from the computationally tuned response of PID controller is considered as a desirable specification and it is used to design the compensator. The different structures of compensator like lead, lag and lead-lag were first simulated in a single area power system and better results are found in Specification Oriented Lead Compensator (SOLC). The simulation study of two area thermal power system with SOLC is then performed and their frequency deviation and tie-line power deviation characteristics are compared with conventional PID controller, Integral controller and also with a non controller system. The Integral Absolute Error (IAE) and Integration Time Absolute Error (ITAE) are considered as performance indices to scrutinize the system robustness. The simulation studies clearly reveal the superiority of the proposed SOLC with PID controller over others in way of enhanced system transient response, improved the stability and robustness of the system. All the simulations in this paper are performed using Matlab software.

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.

scholarly journals Robust H∞ Load Frequency Control of Power Systems Considering Intermittent Characteristics of Demand-Side Resources

Electronics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 593
Author(s):  
Kun Yuan ◽  
Zhetong Ding ◽  
Yaping Li ◽  
Mingyu Huang ◽  
Kaifeng Zhang
Keyword(s):  
Power Systems ◽  
Control Method ◽  
Frequency Control ◽  
Load Frequency Control ◽  
Linear Matrix ◽  
Intermittent Control ◽  
Demand Side ◽  
Load Frequency ◽  
The Stability ◽  
The Impact

Recently, demand-side resources (DSRs) have proceeded to participate in frequency control of the power systems. Compared with traditional generation-side resources, DSRs have unique intermittent characteristics. Taking aggregation of air conditions as an example, they must take a break after providing power support for a period of time considering the user comfort. This behavior, known as the intermittent characteristic, obviously affects the stability of the power systems. Therefore, this paper designs a corresponding controller for DSRs based on the intermittent control method. The designed controller is incorporated into the traditional load frequency control (LFC) system. The time delay is also considered. A rigorous stability proof and the robust H ∞ performance analysis is presented for the new LFC system. Then, the sufficient robust frequency stabilization result is presented in terms of linear matrix inequalities (LMIs). Finally, a two-area power system is provided to illustrate the obtained results. The results show that the designed intermittent controller can mitigate the impact of intermittent characteristics of DSRs.

scholarly journals A Comprehensive Review of the Cyber-Attacks and Cyber-Security on Load Frequency Control of Power Systems

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3860
Author(s):  
Athira M. Mohan ◽  
Nader Meskin ◽  
Hasan Mehrjerdi
Keyword(s):  
Power Systems ◽  
Power System ◽  
Cyber Security ◽  
Distribution Systems ◽  
Frequency Control ◽  
Cyber Attacks ◽  
Load Frequency Control ◽  
Comprehensive Review ◽  
Load Frequency ◽  
The Stability

Power systems are complex systems that have great importance to socio-economic development due to the fact that the entire world relies on the electric network power supply for day-to-day life. Therefore, for the stable operation of power systems, several protection and control techniques are necessary. The power system controllers should have the ability to maintain power system stability. Three important quantities that should be effectively controlled to maintain the stability of power systems are frequency, rotor angle, and voltage. The voltage control in power systems maintains the voltage and reactive power within the required limits and the power factor control enhances the efficiency of power distribution systems by improving load power factors. Among various controls, the frequency control is the most time-consuming control mechanism of power systems due to the involvement of mechanical parts. As the control algorithms of frequency stabilization deliver control signals in the timescale of seconds, load frequency control (LFC) systems cannot handle complicated data validation algorithms, making them more vulnerable to disturbances and cyber-attacks. In addition, the LFC system has extended digital layers with open communication networks and is designed to operate with less human intervention. Moreover, the frequency fluctuation due to load change or cyber-attack in one area affects all other interconnected areas, and thus threatens the stability of the entire network. Due to these circumstances, research activities are still carried out in the field of frequency control and cyber-security. In this paper, a comprehensive review of the cyber-security of the LFC mechanism in the power system is presented. The highlights of the paper include the identification of attack points of different configurations of the LFC system, discussion of the attack strategies, formulation of various attack models, and a brief review of the existing detection and defense mechanisms against cyber-attacks on LFC.

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