A LQG Based Load Frequency Controller in a Competitive Electricity Environment

2005 ◽  
Vol 2 (2) ◽  
Author(s):  
Barjeev Tyagi ◽  
S.C. Srivastava
Keyword(s):  
Electricity Market ◽  
Pid Controller ◽  
Frequency Control ◽  
Test System ◽  
Frequency Regulation ◽  
State Variables ◽  
Linear Quadratic ◽  
Linear Quadratic Gaussian ◽  
Modeling Uncertainties ◽  
Frequency Controller

This paper presents the design of a Linear Quadratic Gaussian (LQG) regulator for the frequency control of a multi-area power system in a restructured competitive electricity market environment. A general model of the LQG regulator has been developed for multi-area system (with hydro and thermal generators) having Poolco and bilateral transactions. To account for the modeling uncertainties and non-measurable states, a Kalman filter has been designed to estimate the state variables. The controller uses these estimates, optimizes a given performance index, and reschedules the generators’ outputs according to their bids for the frequency regulation. The functioning of the proposed LQG regulator has been demonstrated on a four area test system and the results have been compared with those obtained by using an optimal PID controller.

scholarly journals Optimal linear quadratic Gaussian control based frequency regulation with communication delays in power system

2022 ◽  
Vol 12 (1) ◽  
pp. 157
Author(s):  
Hoan Bao Lai ◽  
Anh-Tuan Tran ◽  
Van Huynh ◽  
Emmanuel Nduka Amaefule ◽  
Phong Thanh Tran ◽  
...  
Keyword(s):  
Time Delay ◽  
Power System ◽  
Control Area ◽  
Frequency Regulation ◽  
Feedback Gain ◽  
Communication Delays ◽  
State Variables ◽  
Linear Quadratic ◽  
State Matrix ◽  
Linear Quadratic Gaussian

<p>In this paper, load frequency regulator based on linear quadratic Gaussian (LQG) is designed for the MAPS with communication delays. The communication delay is considered to denote the small time delay in a local control area of a wide-area power system. The system is modeled in the state space with inclusion of the delay state matrix parameters. Since some state variables are difficult to measure in a real modern multi-area power system, Kalman filter is used to estimate the unmeasured variables. In addition, the controller with the optimal feedback gain reduces the frequency spikes to zero and keeps the system stable. Lyapunov function based on the LMI technique is used to re-assure the asymptotically stability and the convergence of the estimator error. The designed LQG is simulated in a two area connected power network with considerable time delay. The result from the simulations indicates that the controller performed with expectation in terms of damping the frequency fluctuations and area control errors. It also solved the limitation of other controllers which need to measure all the system state variables.</p>

scholarly journals Enhanced Performance of Modified PID Load Frequency Controller with Frequency Control Techniques of WU for two Area Interconnected System

2019 ◽  
Vol 8 (6) ◽  
pp. 431-439
Keyword(s):  
Pid Controller ◽  
Frequency Control ◽  
Research Work ◽  
Frequency Regulation ◽  
Interconnected System ◽  
Environment Simulation ◽  
Derivative Filter ◽  
Inertial Control ◽  
Frequency Controller ◽  
Tie Line

This paper demonstrates a modified PID controller that gives enhanced performance in terms of amplitude of first peak, overshoot, and time of settling. The significance of this research work stems from the point that modified PID controller for unit of wind power (WU) with inertial control (C-I), integration of controller of inertial and droop (C-D), and integration of controller of inertial, droop, and pitch angle (C-P) has not been counted in literature so far in totality. In addition, the same controller is not implemented for the TP with WU for C-P with different step load perturbations. The suggested controller is established by cascading of derivative filter with PID controller to restrict the noise sensitivity in PID controller. For validation of the proposed controller, it is employed in different scenario and compared its performance with conventional PID controller. Also, this article compares different frequency regulation techniques of WU separately and gets the best possible combination of controller to offer the boosted performance of the system. The suggested controller has been simulated in MATLAB/SIMULINK ver. 2013 environment. Simulation results show the reductions in frequency deviation and tie line power deviation when TP is subjected to modified PID controller. The major contribution of this work is to advance regulation of frequency and power, which leads to enhanced grid stability.

scholarly journals PI and LQR controllers for Frequency Regulation including Wind Generation

2018 ◽  
Vol 8 (5) ◽  
pp. 3711 ◽  
Author(s):  
Semaria Ruiz ◽  
Julian Patiño ◽  
Jairo Espinosa
Keyword(s):  
Power Systems ◽  
Wind Turbines ◽  
Frequency Control ◽  
Test System ◽  
Performance Comparison ◽  
Load Frequency Control ◽  
Superior Performance ◽  
Frequency Regulation ◽  
Control Effort ◽  
Load Frequency

<pre>The increasing use of renewable technologies such as wind turbines in power systems may require the contribution of these new sources into grid ancillary services, such as Load Frequency Control. Hence, this work dealt with the performance comparison of two traditional control structures, PI and <span>LQR</span>, for secondary regulation of Load Frequency Control with the participation of variable-speed wind turbines. For this purpose, the doubly-fed induction generator wind turbine was modeled with additional control loops for emulation of the inertial response of conventional machines for frequency regulation tasks. Performance of proposed strategies was verified through simulation in a benchmark adapted from the <span>WSCC</span> 3 machines 9-bus test system. Results showed overall superior performance for <span>LQR</span> controller, although requiring more strenuous control effort from conventional units than PI control.</pre>

scholarly journals Load Frequency control(LFC) of a Multiarea Restructured Hybrid Powersystem on Multi objective SSA

2019 ◽  
Vol 9 (2S3) ◽  
pp. 395-402
Keyword(s):  
Frequency Control ◽  
Test System ◽  
Optimization Techniques ◽  
Load Frequency Control ◽  
Dynamic Responses ◽  
Double Integral ◽  
Load Frequency ◽  
Multiobjective Approach ◽  
Integral Controller ◽  
Frequency Controller

The aimof the paper tune the paramters of the load frequency controller using a latest and novel algorithm named as Salp sarm of algorithm with multiobjective approach. The test system choosen is a Two area interconnected hybrid power system under deregulated-environment integrated with Distributd genertion (DG) resource.The DG systems consists of Windturbine generator(WTG), SolarPV systems, Diesels engines generators(DEG), Fuelcells with Aqua electrolyzers and Energy storages like Batteries energy storage systems(BESS). To minimise the frequency of oscillations, Secondarycontroller opted was an optimal Fuzzy PID plus double integral controller (FPID-II). The effectiveness of proposed controller is determined with the comparison of nominal PI, PID and Two degree freedom PID (TDOFPID) controller. Furthermore the dynamic responses of SSA tuned FPID-II controller are been compared with other optimization techniques. The results depit the superiority of the proposed controller in suppressing the deviations of frequency

scholarly journals Frequency Performance Distribution Index for Short-Term System Frequency Reliability Forecast Considering Renewable Energy Integration

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2945
Author(s):  
Kofi Afrifa Agyeman ◽  
Ryota Umezawa ◽  
Sekyung Han
Keyword(s):  
Renewable Energy ◽  
Frequency Control ◽  
Storage System ◽  
Energy Storage System ◽  
Operational Reliability ◽  
Test System ◽  
Frequency Regulation ◽  
Energy Integration ◽  
Short Term ◽  
System Frequency

Risk in a power system’s ability to survive imminent disturbances without recourse to low operational cost and non-interruptive energy delivery remains the responsibility of every grid operator. Intermittencies in renewable energy and dynamic load variations influence the quality of power supply. The sudden changes affect the system frequency, compromising the reliability of the system grid; generation response to frequency regulation is momentous in such an incident. Slower response or smaller reserve capacity may cause a power shortage. This paper proposes a novel predictive scheme for a short-term operational reliability evaluation for system operations planning. The proposed method evaluates the operational reliability of system frequency whiles considering high renewable power penetration and energy storage system incorporation. Required energy generations, and other grid parameters, are modelled as stochastic inputs to the framework. We formulate a reliability index as a frequency distribution considering system frequency control dynamics and processes. The IEEE Reliability Test System (RTS) is used to prove the efficacy of the proposed model.

scholarly journals Optimal load frequency control through combined state and control gain estimation for noisy measurements

2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Anju G. Pillai ◽  
Elizabeth Rita Samuel ◽  
A. Unnikrishnan
Keyword(s):  
Frequency Control ◽  
The State ◽  
Feedback Stabilization ◽  
Load Frequency Control ◽  
Feedback Gain ◽  
State Variables ◽  
Linear Quadratic ◽  
System Parameters ◽  
Load Frequency ◽  
Optimal Load

AbstractCombined estimation of state and feed-back gain for optimal load frequency control is proposed. Load frequency control (LFC) addresses the problem of controlling system frequency in response to disturbance, and is one of main research areas in power system operation. A well acknowledged solution to this problem is feedback stabilization, where the Linear Quadratic Regulator (LQR) based controller computes the feedback gain K from the known system parameters and implements the control, assuming the availability of all the state variables. However, this approach restricts control to cases where the state variables are readily available and the system parameters are steady. Alternatively, by estimating the states continuously from available measurements of some of the states, it can accommodate dynamic changes in the system parameters. The paper proposes the technique of augmenting the state variables with controller gains. This introduces a non-linearity to the augmented system and thereby the estimation is performed using an Extended Kalman Filter. This results in producing controller gains that are capable of controlling the system in response to changes in load demand, system parameter variation and measurement noise.

scholarly journals RobustH2/H∞Control for the Electrohydraulic Steering System of a Four-Wheel Vehicle

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Min Ye ◽  
Quan Wang ◽  
Shengjie Jiao
Keyword(s):  
Hydraulic System ◽  
Pid Controller ◽  
External Disturbance ◽  
Steering System ◽  
Control Performance ◽  
Vehicle Model ◽  
Linear Quadratic ◽  
Linear Quadratic Gaussian ◽  
Steering Angle ◽  
Sensitive Function

To shorten the steer diameter and to improve the maneuverability flexibility of a construction vehicle, four wheels’ steering system is presented. This steering system consists of mechanical-electrical-hydraulic assemblies. Its diagram and principle are depicted in detail. Then the mathematical models are derived step by step, including the whole vehicle model and the hydraulic route model. Considering the nonlinear and time-varying uncertainty of the steering system, robustH2/H∞controller is put forward to guarantee both the system performance and the robust stability. TheH∞norm of the sensitive function from the parameter perturbation of the hydraulic system to the yaw velocity of the vehicle is taken as the evaluating index of the robustness and theH2norm of the transfer function from the external disturbance to the steering angle of the wheel as the index of linear quadratic Gaussian. The experimental results showed that the proposed scheme was superior to classical PID controller and can guarantee both the control performance and the robustness of the steering system.

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