Three-area Power System Research Articles

A Novel ANFIS Controller for LFC in RES Integrated Three-Area Power System

A Novel ANFIS Controller for LFC in RES Integrated Three-Area Power System

A hybrid SCSO-QNN approach based load frequency control of three area power system with renewable sources using FOPID controller

ABSTRACT This research proposes a hybrid SCSO-QNN method for designing a FOPID controller in a three-area power system to regulate load frequency. The proposed hybrid approach combines quantum neural networks with sand cat swarm optimization, and it is commonly named as the SCSO-QNN method. The proposed method’s primary goal is to overcome load disturbances and attain the intended output of the interconnected system. The SCSO generates controller parameters tuned by the FOPID controller, providing a significant improvement in performance, while the QNN is employed to forecast the optimal control signal of the converter. Reducing steady-state errors and improving system stability are areas where the FOPID performs better than a traditional integer-order PID controller. Moreover, SCSO-QNN optimization technique exhibits excellent convergence properties, resulting in improved control performance. The proposed method ensures system frequency control by controlling frequency deviation and power fluctuations in the connect line during load disturbances. The proposed method is executed on the MATLAB platform and contrasted with current techniques. The proposed technique outperforms all current techniques, including ABC-FOPID, Genetic Algorithm, and Artificial Bee Colony PID. The proposed method Area control error is 1.8%, which is less than other existing methods.

A Novel Failure-Distribution-Dependent Non-Fragile $H_\infty$ Fault-Tolerant Load Frequency Control for Faulty Multi-Area Power Systems

This paper studies the non-fragile <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$H_\infty$</tex-math></inline-formula> fault-tolerant load frequency control problem for multi-area power systems with actuator failures. At first, considering the distribution characteristics of partial failures, a stochastic distribution model is established for actuator partial failures. Next, for the perturbations of controller gains, not only the additive uncertainties but also the multiplicative uncertainties are incorporated into the fault-tolerant controller design. The coupling items which hardly directly solved have turned into a W-problem in fault-tolerant load frequency control. Furthermore, a novel failure-distribution-dependent non-fragile <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$H_\infty$</tex-math></inline-formula> fault-tolerant load frequency control algorithm is given by using linear matrix inequalities technology and Lyapunov-Krasovskii functional method. Finally, a numerical example with a three-area power system are given to show the effectiveness of the proposed methods.

Event-triggered data-driven load frequency control for multi-area power system with wind penetration under deregulation environment

In order to solve the problem of power exchange between areas of multi-area power systems under the power market, this paper designs a power trading contract based on the generation participation matrix, so as to simulate the specific process of power change in each area. With the integration of wind power into the large-scale power system, it is difficult to model the multi-area power system. For this situation, this paper designs a data-driven model-free adaptive load frequency control algorithm based on collecting input and output data, which gets rid of the dependence of the power system on the model. Along with the frequent transmission of input and output data in each area, the communication load of the power system also increases. Aiming at saving communication resources, this paper designs an event-triggered mechanism to reduce the communication bandwidth. The stability of the control algorithm is demonstrated theoretically. Finally, a three-area power system with wind penetration is used as an example to simulate and verify the effectiveness of the proposed algorithm in this paper.

An instant inertia estimated and operation burden considered frequency regulation method for low inertia power systems

The application of virtual inertia (VI) has become a novel solution and new orientation for the frequency regulation of the high variable renewable energy (VRE) penetrated low inertia systems. How to provide a frequency regulation strategy for the system with VI is a key problem. Firstly, the power system is a multi inputs multi outputs (MIMO) system, in which the coupling characteristics of VI control and the primary and secondary frequency controls can’t be ignored. Secondly, the system inertia constant is time-varying and the estimation of it is crucial for gaining a satisfying regulation performance. This paper intends to provide a frequency regulation strategy for this problem. In this work, an Elman neural network (ENN) based inertia estimation with a deadband method is proposed for the identification of the system’s instant inertia. And the Laguerre function-based rate of change of frequency (ROCOF) constrained MIMO-MPC is constructed to provide the collaboration strategy. Then, the control parameters are tuned by the gravitational search algorithm (GSA) considering both the system performance indexes and the operation burden indexes. The proposed strategy is testified based on a three-area power system. The results prove not only the robustness of the controller but also the effectiveness of the ROCOF constraint, the operation burden index, and the instant inertia estimation method.

Artificial Raindrop Algorithm-Based Load Frequency Control in PV-Thermal-Thermal Interconnected Power System

Nowadays Grid connected photovoltaic (PV) systems increases its influence in Indian power system. The current rise in load and demand means that linked power networks are essential. The efficiency of a load is significantly impacted by power quality issues, especially when it comes to frequency. The power system’s frequency and tie-line power should be as close as possible to the anticipated specifications. This article proposes artificial raindrop method with proportional- integral (PI) controller, to manage the load frequency control (LFC) of a PV-thermal-thermal interconnected three-area power system. A meta-heuristic method that takes inspiration from natural rainfall is the proposed artificial raindrop algorithm. A comparison is made between the suggested system and standard PI controller. A number of loads are simulated using Matlab to assess the full system. To validate the performance of proposed system, it is compared with the LFC using PI and fuzzy gain scheduling controller. Matlab is used to evaluate the entire system with varying loads. Take into account area 1 in 10% load perturbation: FGS reduces frequency deviation undershoot by 22% compared to the PI controller, while the ARD algorithm reduces it by 32%, where PI results in an undershoot of 0.1781 Hz.

Regulation of multi-area power system load frequency in presence of V2G scheme.

The integration of renewable sources (RSs) and the widespread deployment of electric vehicles (EVs) has transitioned from a luxury to a necessity in modern power systems. This results from the sharp increase in electric power demand and public awareness of switching to green energy. However, in addition to load fluctuations and changes in system parameters, these RSs and EVs negatively impact the load frequency (LF). This work presents a LF control for a modern multi-area power system incorporating photovoltaic (PV) and EV chargers. The proposed controller primarily utilizes EV chargers within modern power systems. This approach offers the advantage of using the already present components instead of introducing new ones. The proposed controller comprises the ecological optimization approach (ECO) and the integral controller (I). Both of these components are designed for autonomous vehicle-to-grid (V2G) devices. The proposed control technique is applied to a three-area power system, where the V2G scheme is located in Area-1. Variations in the load, PV power generated, and system parameters are considered to evaluate the effectiveness of the proposed (I+ECO+V2G) controller for controlling the LF. To assess the performance of the proposed I+ECO+V2G system, a comparative analysis is conducted to compare its performance with both the I+ECO system and the standard I-controller. The simulation findings demonstrate that implementing the I+ECO and the proposed I+ECO+V2G strategies results in enhanced system stability and decreased LF fluctuations compared to the conventional I-control approach. Furthermore, while comparing the I+ECO control technique to the suggested control strategy I+ECO+V2G, it was seen that the latter reaches steady state values more quickly. The results validate the robustness and effectiveness of the proposed controller in mitigating the impacts of load disturbances, uncertainties, and nonlinearities within the system. These simulations were performed using MATLAB/SIMULINK. To validate the outcomes of the simulation results, an experimental setup consisting of a real-time dSPACE DS1103 connected to another PC via QUARC pid_e data acquisition card was used. The experimental findings have substantiated the accuracy of the simulation findings about the superiority of the I+ECO+V2G methodology compared to both the I+ECO and I-control methodologies concerning system performance and LF control.

Modern PID/FOPID controllers for frequency regulation of interconnected power system by considering different cost functions

This article presents frequency regulation of an interconnected three-area power system (Thermal + Wind + Hydro). Fractional Order PID (FOPID) and Proportional-Integral-Derivative (PID) controllers are applied as subsidiary regulators to control the electrical power interconnected system at the time of sudden load variation. To accomplish this study, Genetic Algorithm (GA), Grey Wolf Optimizer (GWO), Sine Cosine Inspired Algorithm (SCIA) and Atom Search Inspired Algorithm (ASIA) are implemented to optimize the secondary regulators' gains (PID and FOPID) by considering various cost functions such as Integral Absolute Error (IAE), Integral Time Absolute Error (ITAE), Integral Square Error (ISE), and Integral Time Square Error (ITSE). Performance analysis in this work is conducted using various cost functions based on GA, GWO, SCIA and ASIA. The comparative analysis of the attained results reveals that GWO-PID and ASIA–PID settle at (83.83 s) and (30.31 s), respectively and ASIA-FOPID at (25.12 s). The controllers based on ITSE as a cost function outperform the comptrollers with other cost functions (ISE, IAE and ITAE). In addition, the ISE-based GA–PID and SCIA–PID settle at (113.92 s) and (35.1 s), respectively and SCIA-FOPID at (24.78 s). The ISE-based regulators yield improved response equated to other cost functions (ITSE, IAE and ITAE) optimized controllers. The robustness test also is carried out to validate the effectiveness of the proposed optimization techniques by changing the system parameters within ± 25% and ± 50% from their nominal values as well as changing the load pattern.

Adaptive robust FDI attack detection for cyber–physical​ systems with disturbance

This paper investigates the problem of attack detection for cyber–physical systems (CPSs) with disturbances, measurement noises, and false data injection (FDI) attacks. A classical linear discrete-time system attack model is constructed and a robust attack detector based on the mixed H_/H ∞ is designed. Firstly, a system with an actuator that suffered a malicious attack is modeled. Then, a robust attack detector based on the mixed H_/H ∞ is designed in which the H_ index and H ∞ index are used to characterize the sensitivity to attacks and robustness to disturbances and measurement noises, respectively. And an adaptive detection threshold with a compensation term is proposed. Besides, the designed robust attack detector enables the attack detection dynamic system to be asymptotically stable and to guarantee the H_/H ∞ performance, and the robust attack detector gains are solved from a convex optimization. Finally, the obtained theoretical results are validated through a numerical simulation and a three-area power system simulation.

Inertia estimation of multi-area power systems using tie-line measurements and modal sensitivity analysis

The replacement of conventional synchronous generators with converter-interfaced renewable energy sources (RESs) reduces the overall inertia levels of modern power systems, leading to frequency stability issues. Moreover, the intermittent nature of RESs constitutes system inertia variable during the day, further complicating the frequency control procedure. Therefore, power system operators shall estimate close to real-time the overall inertia levels of their grids in order to ensure their secure and reliable operation. In this context, in this paper, a new methodology for the inertia estimation of multi-area power systems is formulated. The proposed method uses the modal sensitivity matrix to obtain a linear approximation of the relation between modal parameters and inertia constants. During the real-time operation, modal parameters are identified via system responses using the Matrix Pencil method. The identified modes and the derived sensitivity matrix are used to estimate the overall inertia of the examined power system. The effectiveness of the proposed method is validated by means of simulations performed in one-area, two-area, and three-area power system models.

Load frequency control in three-area single unit power system considering non-linearities effect

Load frequency control is always a crucial aspect in delivering quality power in integrated power system. This paper proposes an optimally tuned Proportional-Integral-Derivative (PID) controller to remove frequency errors caused by unexpected load fluctuations while ensuring tie-line power exchange. Moreover, the threearea power system with non-linearities such as Generation Rate Constraint and Governor Dead Band has been investigated. For tuning the parameters of PID controller Improved Grey Wolf Optimization (IGWO) has been used. The dynamic response of optimized PID controller have been compared with the result obtained from Genetic Algorithm (GA), Particle Swarm Optimization (PSO), and Sine Cosine Algorithm (SCA).

Load frequency composite control for multi-region interconnected power systems

This paper investigates a composite controller for load frequency control (LFC) in multi-region interconnected power systems via sliding mode observer design. State observers (SOs) and disturbance observers (DOs) are implied for the LFC based on the load variations with communication delays and quantization output measurements. A nonlinear integral sliding surface combined with a composite controller is developed to optimize control performance. Moreover, a three-area power system model is used to demonstrate the effectiveness of the proposed scheme in the illustrative example, confirming that frequency deviations can be rejected despite delays, uncertainties, and quantization during transmission.

Decentralized event-triggered sliding mode scheme for frequency regulation of multi-area power systems under deception attacks

This paper investigates the frequency regulation problem of networked multi-area power systems subject to random deception attacks. Due to the increasing integration of wireless communication devices in power systems, the frequency stability highly relies on the efficiency and security of information transmission. To alleviate the communication burden, a decentralized dynamic event-triggered (ET) scheme is proposed, in which each area transmits the measurement via its own ET rule. Moreover, the coefficients of dynamic variables are designed based on the state variations and the attack probability for different areas. Then, a decentralized ET sliding mode controller is proposed to restore the frequency. Both the mean square exponentially ultimate boundedness of the power systems and reachability of the specified sliding surface are analyzed, and the corresponding conditions are given. Compared with the widely adopted centralized schemes, the proposed decentralized ET control scheme is easier to implement and can ensure more reasonable transmission considering attack probability for different areas; meanwhile, the deception attacks on different areas are considered to occur independently. Finally, simulation results of a three-area power system are provided.

A novel primary frequency control framework for multi-area power systems containing battery energy storage systems

Power system frequency response analysis is generally conducted on a single-area power system model due to fast and simple calculations. However, to obtain more accurate results of the system frequency dynamics, a frequency response analysis should be conducted on a multi-area power system model. In a multi-area power system, the frequency during disturbances can manifest itself differently in certain areas in the initial moments following a disturbance. As a result, generating units located in the distant areas contribute to the primary frequency control (PFC) with a certain time delay due to wave propagation. To overcome this issue, this paper introduces a novel method for a PFC mechanism. The main goal is to allow generators in remote areas to start changing the output power earlier, much before the wave propagates to that area. To achieve the desired result, the control of battery energy storage systems (BESS) during participating in PFC is modified to follow the tie-line power flow changes, while turbine generators of synchronous generators receive the frequency signal depending on the disturbance location area. To demonstrate the effectiveness of the proposed method, the results are obtained by simulating a three-area power system model.

Coordinated AGC control strategy for an interconnected multi-source power system based on distributed model predictive control algorithm

The erratic and random characteristics of wind power and wind-thermal replacement significantly degrade the performance of AGC in an interconnected, multi-source power system. For the lack of cooperation between wind power and thermal plants in AGC of interconnected power system as well as the heavy computational burden and inflexible information interaction of centralized AGC architecture, a novel coordinated AGC control strategy for an interconnected multi-source power system based on distributed model predictive control (DMPC) algorithm is proposed in this research. Under the DMPC architecture, the dimension of centralized AGC problem is reduced in each subsystem, and the overall AGC performance can be enhanced through inter-area communication between subsystems. In the meantime, based on the proposed coordinated control strategy, the active AGC response capability of wind farms and energy storage in the interconnected system is exploited to realize the dynamic cooperation between the wind generation and thermal AGC plants, and the overall AGC control performance can be further improved. In this paper, local DMPC controllers are deployed in each subsystem to address the drawbacks of a centralized control architecture by exchanging forecast and state measurement information with neighboring subsystems. In addition, considering the current operating status of multiple kinds of energy sources with different features, a fuzzy-based coordinated control strategy is designed for the purpose of dynamically allocating the AGC demand inside the wind-storage system, and the wind farm’s reliability for AGC response in diverse operation scenarios can be guaranteed. Finally, comparative analysis with existing works has been conducted on a three-area power system, and numerical results demonstrate that the proposed coordinated AGC control strategy has better performance in AGC performance and the dynamic cooperation can be achieved between wind power and thermal plants in AGC response through the designed wind-storage system and coordinated DMPC AGC control strategy.

Load frequency control for wind-integrated multi-area power systems: An area-based event-triggered sliding mode scheme

This paper deals with the load frequency control problem of multi-area power system with doubly-fed-induction-generator-based wind farm. An area-based event-triggered (ET) sliding mode control scheme is proposed to restore the nominal frequency by transmitting less information. The main feature of area-based ET scheme is that each area will transmit its states information to the controller independently via its own triggering mechanism. By flexibly selecting triggering thresholds, the area-based ET scheme can meet the unbalanced network resources among different areas. Meanwhile, the designed sliding mode controller can effectively suppress the fast fluctuation resulting from load and wind generation to achieve frequency restoration and maintain the tie-line power at its scheduled value. The optimization algorithm on the sufficient conditions is given. Finally, the proposed control scheme is illustrated via a three-area power system and IEEE 39-bus system.

Event-Based Distributed Fuzzy Load Frequency Control for Multiarea Nonlinear Power Systems With Switching Topology

This article investigates the event-based distributed fuzzy load frequency control approach for nonlinear interconnected power systems under a switching topology. Specifically, nonlinear factors and uncertain parameters existing in turbine and governor dynamics are modeled and analyzed under the interval type-2 fuzzy method. New memory-based adaptive event-triggered mechanisms, whose directions and threshold parameters are dynamically updated based on the output change trend and relative output error of multiple memories, are proposed to further save network energy. Aiming at communication topology changes in multiarea power systems, a novel switched control system is established by introducing a time-varying communication matrix. Then, the system’s asymptotic stability is ensured by the piecewise Lyapunov–Krasovskii method. Furthermore, to further relax stability conditions, slack matrices are considered with the boundary information of membership functions. Finally, three-area power systems are shown to demonstrate the effectiveness of proposed distributed load frequency control strategies.

Dynamic Event-Triggered Output Feedback Control for Load Frequency Control in Power Systems With Multiple Cyber Attacks

This article presents a novel dynamic event-triggered scheme for the load frequency regulation with periodic denial-of-service (DoS) attacks and deception attacks via decentralized output-based control algorithm. Compared with the existing event-triggered strategy, the proposed one automatically changes the parameters of the triggered condition by detecting the frequency trend of the DoS attack to change the release frequency, which can ensure the stability of the power system while increasing the probability of effective transmission subject to DoS attack and thus, reducing network bandwidth usage. First, the proposed dynamic event-triggered strategy combined with the decentralized output-based controller is presented in a unified framework to deal with deception attacks and DoS attacks in the multiarea power system. Then, we utilize the Lyapunov stability theory to analyze the exponential stability in the mean-square sense and the robustness of the power system. By solving a set of linear matrix inequalities (LMIs), a procedure is given for the design of output-based load frequency controllers. Finally, a three-area power system is exploited as a simulation to verify the effectiveness of the proposed results.

Adaptive Event-Triggered Decentralized Dynamic Output Feedback Control for Load Frequency Regulation of Power Systems With Communication Delays

In order to ensure that the power system frequency and tie-line power remain at the nominal value when the load fluctuates, while reducing the release number of decentralized sensor, this work presents a novel adaptive event-triggered scheme for the load frequency regulation via designing the decentralized dynamic output feedback controller (DOFC), where the communication delay issue is also considered due to communication constraints. Distinct from the existing ones, the proposed adaptive event-triggered strategy automatically tunes the threshold according to the local extremum of the system output signal, which can significantly reduce the number of unnecessary signal transmissions to ensure system performance. First, the proposed adaptive event-triggered transmission scheme is integrated with the decentralized DOFC and communication delays under the framework of a linear time-delay system. Then, the asymptotic stability of the closed-loop power system is analyzed through the Lyapunov stability theory and a procedure is given for the design of decentralized dynamic output load frequency controllers by solving some linear matrix inequalities (LMIs). Finally, a three-area power system is used to verify the effectiveness and usefulness of the proposed results.

Multi-stage Fractional-order Controller for Frequency Mitigation of EV-based Hybrid Power System

This work reports load-frequency-control (LFC) of a three-area hybrid power system incorporating renewables and electric-vehicles (EV). Such a power system with applicable non-linearities necessitates a resilient controller. In this respect, a multi-stage fractional-order proportional-integral-derivative (MSFOPID) controller is explored for the LFC operation of the presented hybrid power system. For the proposed controller, there is a considerable improvement of 81.3% in terms of objective function (ISE value). Similarly, the foible evidence study shows an improvement of 39% with respect to other considered secondary controllers. The active role of EVs in preserving the system dynamics is inspected thoroughly. The impact of redox-flow batteries as an energy storage device and parametric variation of phase-locked-loop for system dynamic control are illustrated. Furthermore, the robustness of explored MSFOPID controller optimized gains is checked against alterations in power-system-loading and renewable energy sources, respectively.