Control Of Interconnected Power Systems Research Articles

Load frequency control of interconnected power system using cuckoo search algorithm

This paper presents a new time-domain multi-objective function approach for solving load frequency control issue in an interconnected power system. The performance of interconnected power system in each area is validated for overshoot and settling time values of frequency change and tie-line power exchange. An objective function is created with the goal of enhancing proportional integral derivative (PID) controller settings by reducing overshoot and achieving faster time-domain settling times. The efficiency of the proposed time-domain multi-objective function is evaluated in a two-area thermal power plant using a nature-inspired cuckoo search optimization (CSA) technique. By comparing the time-domain simulation results of the test system with the existing integral error-based objective functions IAE, ISE, ITAE, and ITSE, the proposed objective function is validated. Further, a sensitivity analysis were carried out to analyze the robustness of the proposed multi-objective function under various uncertain conditions.

Frequency Control of Interconnected Power System via SBO assisted Simultaneous Tuning Strategy in Presence of DFIG

To achieve the objectives of the automatic generation control (AGC) of wind integrated interconnected power system (WIIPS), better tuning and control strategies are required. This paper suggests simultaneous tuning strategy for the AGC and wind system controllers to improve the stability of the WIIPS. The bulk amount of wind is integrated into the grid using the doubly fed induction generator (DFIG) and its simplified model is used to simulate the WIIPS. Initially, classical controllers are opted in AGC mechanism to reduce the frequency disturbances caused by the load and wind generation uncertainties. Further, classical controllers of WIIPS are replaced with cascade controllers to enhance the system frequency profile during the disturbances. The optimal set of solutions of the classical and cascade controllers are examined by the satin bowerbird optimizer (SBO) with the help of integral square error as fitness function of the optimization problem. Comparisons are provided to show the merits of the WIIPS over normal interconnected power system, cascade controller over classical controller and simultaneous tuning strategy over regular tuning mechanism.

Cyber Security of Smart-Grid Frequency Control: A Review and Vulnerability Assessment Framework

Smart Grid involves application of Information and Communication Technology (ICT) for monitoring, protection, operation, and control of interconnected power systems under various scenarios. Smart Grid Control (SGC) is an important aspect that is constantly subjected to various vulnerabilities, threats, and attacks under central and distributed control architectures. Cyber Security of smart grid control, especially, Load Frequency Control (LFC) is an important issue that is addressed in this article. The state-of-the-art in cyber security and attacks on smart grid control and intensive literature review is discussed with a comprehensive list of references on LFC. The authors present a part of their own work carried out on a systematic Vulnerability Assessment (VA) framework that can be used to identify weak points in the LFC system. The proposed methodology is explained for Vulnerability Assessment of the standard 39-bus New England test system and the 96 bus reliability test system to illustrate the concept of cyber security and Vulnerability Assessment of smart grid LFC.

Frequency Control of Interconnected Power System via SBO assisted Simultaneous Tuning Strategy in Presence of DFIG

To achieve the objectives of the automatic generation control (AGC) of wind integrated interconnected power system (WIIPS), better tuning and control strategies are required. This paper suggests simultaneous tuning strategy for the AGC and wind system controllers to improve the stability of the WIIPS. The bulk amount of wind is integrated into the grid using the doubly fed induction generator (DFIG) and its simplified model is used to simulate the WIIPS. Initially, classical controllers are opted in AGC mechanism to reduce the frequency disturbances caused by the load and wind generation uncertainties. Further, classical controllers of WIIPS are replaced with cascade controllers to enhance the system frequency profile during the disturbances. The optimal set of solutions of the classical and cascade controllers are examined by the satin bowerbird optimizer (SBO) with the help of integral square error as fitness function of the optimization problem. Comparisons are provided to show the merits of the WIIPS over normal interconnected power system, cascade controller over classical controller and simultaneous tuning strategy over regular tuning mechanism.

Robust deep Koopman model predictive load frequency control of interconnected power systems

Robust deep Koopman model predictive load frequency control of interconnected power systems

A General Resiliency Enhancement Framework for Load Frequency Control of Interconnected Power Systems Considering Internet of Things Faults

A General Resiliency Enhancement Framework for Load Frequency Control of Interconnected Power Systems Considering Internet of Things Faults

Load Frequency Control and Automatic Voltage Regulation in Four-Area Interconnected Power Systems Using a Gradient-Based Optimizer

Existing interconnected power systems (IPSs) are being overloaded by the expansion of the industrial and residential sectors together with the incorporation of renewable energy sources, which cause serious fluctuations in frequency, voltage, and tie-line power. The automatic voltage regulation (AVR) and load frequency control (LFC) loops provide high quality power to all consumers with nominal frequency, voltage, and tie-line power deviation, ensuring the stability and security of IPS in these conditions. In this paper, a proportional integral derivative (PID) controller is investigated for the effective control of a four-area IPS. Each IPS area has five generating units including gas, thermal reheat, hydro, and two renewable energy sources, namely wind and solar photovoltaic plants. The PID controller was tuned by a meta-heuristic optimization algorithm known as a gradient-based optimizer (GBO). The integral of time multiplied by squared value of error (ITSE) was utilized as an error criterion for the evaluation of the fitness function. The voltage, frequency, and tie-line power responses of GBO-PID were evaluated and compared with integral–proportional derivative (GBO-I-PD), tilt integral derivative (GBO-TID), and integral–proportional (GBO-I-P) controllers with 5% step load perturbation (SLP) provided in each of the four areas. Comprehensive comparisons between GBO-PID and other control methodologies revealed that the proposed GBO-PID controller provides superior voltage, frequency, and tie-line power responses in each area. The reliability and efficacy of GBO-PID methodology were further validated with variations in the turbine time constant and speed regulation over a range of  ± 25%. It is evident from the outcomes of the sensitivity analysis that the proposed GBO-PID control methodology is very reliable and can successfully stabilize the deviations in terminal voltage, load frequency, and tie-line power with a shorter settling time in a four-area IPS.

Load Frequency Control of Interconnected Power System with Renewables using Improved Fractional Integral Controller

Load Frequency Control of Interconnected Power System with Renewables using Improved Fractional Integral Controller

Improved load frequency control of interconnected power systems using energy storage devices and a new cost function

Improved load frequency control of interconnected power systems using energy storage devices and a new cost function

System Dynamics and Frequency Regulation of a Multi-Area Power System Using an Optimal Controller

For system frequency control, the current work proposes a multi-area power system integrating various renewable sources. An effective controller with intrinsic superior capabilities of restricting peak deviation, steady state errors, and oscillatory behavior of a dynamic system is an apparent alternative for autonomous generation control of interconnected power systems. The most difficult part of using a controller is figuring out how to get the most out of it. Because of its space complexity, the trial and error method of determining the benefit by indirect optimization with an acceptable performance index appears to be insufficient. As a result, it appears that using an effective algorithm technique to find the maximum gains for the controllers is the best option. The gains of the controllers are addressed in this work and thus are optimized using a meta-heuristic technique in this study.

Novel chaos game optimization tuned-fractional-order PID fractional-order PI controller for load\u2013frequency control of interconnected power systems

In this work, chaos game optimization (CGO), a robust optimization approach, is employed for efficient design of a novel cascade controller for four test systems with interconnected power systems (IPSs) to tackle load–frequency control (LFC) difficulties. The CGO method is based on chaos theory principles, in which the structure of fractals is seen via the chaotic game principle and the fractals’ self-similarity characteristics are considered. CGO is applied in LFC studies as a novel application, which reveals further research gaps to be filled. For practical implementation, it is also highly desirable to keep the controller structure simple. Accordingly, in this paper, a CGO-based controller of fractional-order (FO) proportional–integral–derivative–FO proportional–integral (FOPID–FOPI) controller is proposed, and the integral time multiplied absolute error performance function is used. Initially, the proposed CGO-based FOPID–FOPI controller is tested with and without the nonlinearity of the governor dead band for a two-area two-source model of a non-reheat unit. This is a common test system in the literature. A two-area multi-unit system with reheater–hydro–gas in both areas is implemented. To further generalize the advantages of the proposed scheme, a model of a three-area hydrothermal IPS including generation rate constraint nonlinearity is employed. For each test system, comparisons with relevant existing studies are performed. These demonstrate the superiority of the proposed scheme in reducing settling time, and frequency and tie-line power deviations.

Online Koopman Mode Decomposition for Power System Synchrophasor Data

Measurement of power system oscillations is the first step for monitoring and control of interconnected power systems. Koopman Mode Decomposition (KMD) is a novel technique of nonlinear time-series analysis guided by the spectral theory of Koopman operators for nonlinear dynamical systems. This paper presents an online algorithm of KMD that is suitable to streaming data derived from synchrophasors. Its effectiveness is established by applying it to extract an inter-area mode of the Japan's western power system directly from synchrophasor data at three locations.

Coordinated automatic generation control of interconnected power system with imitation guided exploration multi-agent deep reinforcement learning

An intelligent automatic generation control (IAGC) framework is proposed to address the coordination problems between AGC controllers in multi-area power systems. In this framework, every area of the power system consists of an adaptive proportional-integral (PI) controller that employs a tuner to regulate coefficients in real time. The tuner of each adaptive proportional-integral (PI) controller adopts an imitation guided-exploration multi-agent twin-delayed deep deterministic policy gradient (IGE-MATD3) algorithm, thereby realizing a multiarea coordinated AGC. To improve the robustness and adaptability of the IAGC framework, the proposed algorithm incorporates imitation learning and outputs the optimal coordinate control strategy of several controllers. As demonstrated by a simulation of the China Southern Grid four-area power system model, an IAGC framework can improve dynamic control performance and reduce the regulation mileage payment of the operator in every area.

Robust Load Frequency Control of Interconnected Power System in Smart Grid

In this paper, the coordinated control of vehicle to grid (V2G) power control and proportional-integral (PI) tuned with particle swarm optimization (PSO), based on H-infinity control, are integrated to control the frequency regulation of interconnected power system in Smart Grid (SG) environment. The plug-in hybrid electric vehicle (PHEV) can compensate the deficient load frequency control (LFC) capacity. In this way V2G power control is applied to compensate for the LFC capacity. For charging the batteries, power is supplied from grid-to-vehicle (G2 V). The traditional controller performance is compared for working with multiple uncertainty-based H∞ controllers and the results proved the predominant performance of the proposed control. To check the system robustness against uncertainty, the PI controller gain and State of Charge (SOC) deviation are optimized using the PSO-based multiple uncertainty-based H∞ controller. Different specimens have been analyzed to ensure the entire working of the developed model. A series of simulation results are presented for the dynamic response of power systems which is superior to other design methods obtained from the literature. Simulation results of two-area interconnected intelligent power system show that frequency deviations are minimal and within specified limits.

$$H_{\infty }$$ Performance-Based Sliding Mode Control Approach for Load Frequency Control of Interconnected Power System with Time Delay

This paper proposes a sliding mode control (SMC) approach to design $$H_{\infty }$$ performance-based load frequency controller for interconnected power system (IPS) with time delay. Incorporating an artificial delay, a sliding surface function is designed to enhance dynamic performance of the power system. Linear matrix inequality-based stabilization criterion is derived using Lyapunov–Krasovskii functional for multi-area power system. A novel SMC law is designed with artificial delay to drive the system trajectory into the predefined sliding surface. The applicability of the proposed controller is proved by considering a two-area time-delay IPS. Performance of the controller is verified from the simulation study of the time-delay IPS with proposed controller in MATLAB/Simulink. Then, the controller performance is verified in real time by using OPAL-RT OP4510 digital simulator.

Performance Analysis for Load Frequency Control of Interconnected Power Systems with Different Techniques

In the interconnected power system, frequency is one of the most important criteria determining system stability. Since interconnected systems consist of more than one region, load frequency control (LFC) is very complicated. For this reason, load frequency control analysis has been performed for interconnected power systems consisting of two and four regions in this article. Vortex Search Algorithm (VSA), Salp Swarm Algorithm (SSA) and Sine Cosine Algorithm (SCA) are used to determine the filter coefficient proportional-integral-derivative controller (PID-N) parameters of these interconnected systems. The results obtained are analyzed for % overshoot (%OS), % undershoot (%US) and settling time (ST) values for each region. It is observed that different system performances are obtained using by these methods. In addition, all system performances are significantly improved with the selected methods.

Actuator fault-tolerant load frequency control for interconnected power systems with hybrid energy storage system

Aiming at the problem of hybrid energy storage faults in large interconnected power systems, an integrated fault-tolerant control scheme is proposed to deal with actuator faults and external disturbances. Firstly, the hybrid energy storage system is introduced based on the traditional interconnected power system, and a new topological structure is given. Secondly, the state-space model of each area in the given topological structure is established considering the external disturbance and actuator fault of the power system. Then the sliding mode observer is designed and the fault-tolerant control of interconnected power systems is realized according to the estimated value and sliding mode technology. Finally, the simulation results on the model of four-area interconnected power system show that the proposed observer can realize fault estimation in a short time, and the fault-tolerant control effect is satisfied with nearly 30% reduction of regional control error compared with the traditional method.

Improved model predictive load frequency control of interconnected power system with synchronized automatic generation control loops

BackgroundAutomatic generation control (AGC) of multi-area interconnected power system (IPS) is often designed with negligible cross-coupling between the load frequency control (LFC) and automatic voltage regulation (AVR) loops. This is because the AVR loop is considerably faster than that of LFC. However, with the introduction of slow optimal control action on the AVR, positive damping effect can be achieved on the LFC loop thereby improving the frequency control. In this paper, LFC synchronized with AVR in three-area IPS is proposed. Model predictive controller (MPC) configured in a dense distributed pattern, due to its online set-point tacking is used as the supplementary controller. The dynamics of the IPS subjected to multi-area step and random load disturbances are studied. The efficacy of the developed scheme is ascertained by simulating the disturbed system in MATLAB/Simulink.ResultsBased on the comparative analysis on the system responses, it is established that by cross-coupling the LFC loop with AVR, reductions of 66.45% and 59.09% in the frequency and tie-line power maximum deviations respectively are observed, while the respective settling times are found to be reduced by 29.68% and 22.77% when compared with the uncoordinated control scheme. In addition, the standard deviation and variance of the integral time absolute error of the system’s responses have reduced by 23.21% and 20.83% respectively compared to those obtained in a similar study.ConclusionsThe reduction in the maximum deviations and settling times in the system states indicates that introducing the voltage control via AVR loop has improved the frequency control significantly. While the lower standard deviation and variance of the integral time absolute error signify improvement in the robustness of the developed algorithm. However, this improvement is at the detriment of the controller size and computational complexity. In the uncoordinated control scheme, the control vector is one-dimensional, while in the coordinated scheme, the control vector is two-dimensional for each CA.

Quasi-oppositional JAYA optimized 2-degree-of-freedom PID controller for load-frequency control of interconnected power systems

ABSTRACT An effort is given in this paper, for the first time, to discuss the load-frequency control (LFC) problem of an interconnected power system by implementing a novel heuristic optimization method called quasi-oppositional-based JAYA (QOJAYA). The proposed algorithm houses the knowledge of quasi-oppositional-based learning to enhance convergence speed and find the best solutions to the LFC problem. To show the effectiveness, the proposed QOJAYA scheme is, individually, applied to a two-area multi-unit multi-source power plant and a three-area hydrothermal power plant considering the system nonlinearities. The structural simplicity and performance adequacy of the well-known proportional-integral (PI) controller enforces to optimally design it as a secondary controller at the first instant. Afterward, the dynamic stability of the concerned power systems is increased with a 2DOF-PID controller. The proposed algorithm is employed to search the optimal settings of the said controllers by minimizing the time-based single-valued fitness functions. Simulation results validate the success of the proposed QOJAYA scheme and demonstrate its dominance over original JAYA, teaching-learning-based optimization (TLBO), and other recently introduced optimization techniques in the state-of-the-art for the same power system. Finally, the robustness of the designed controller is established by performing sensitivity analysis considering parameters and loading uncertainties.

Equilibrium optimization algorithm for automatic generation control of interconnected power systems

Equilibrium optimization algorithm for automatic generation control of interconnected power systems