Design Of Power Control System Research Articles

Resilient Reliable Hθ Load Frequency Control of Power System With Random Gain Fluctuations

This article proposes a resilient reliable H∞ load frequency control (LFC) design for power system involving the external load disturbances, stochastic actuator failures, and randomly occurring gain fluctuations. In this regard, the separate random variables are introduced which characterize the actuator failures and gain fluctuations in an individual manner that satisfies the Bernoulli distribution. The resilient reliable proportional-integral (PI)-type LFC is proposed by utilizing the resilient control scheme and the reciprocal convex technique along with the Lyapunov-Krasovskii functional (LKF), which guarantees the mean-square asymptotic stability of power system via H∞ performance index. Finally, the simulations are given to ensure the less conservative results of the proposed method when compared to the existing results.

Parameters determination of time-delayed embedding with application to Koopman operator-based model predictive frequency control

Power systems around the world have been registering a degenerating inertial response in view of the growth of inverter-based resources along with the withdrawal of conventional coal units. Therefore, there is a need for swift frequency support and its control, preferably by means of power electronic-interfaced storage devices, owing to their beneficial capabilities. Despite being particularly efficient, pragmatically, the traditional model-based non-linear control techniques are not highly popular in power system control design, primarily due to the complications faced in obtaining accurately suitable models for certain power system components. Lately, the modelfree Koopman operator-based model predictive control (KMPC) has proven to be highly conducive for data-driven non-linear control design. The principle behind KMPC is to change the coordinates in a manner to get an approximately linear model, which can then be controlled using a linear model predictive control. In this study, we employed time-delayed embedding of measurements to reconstruct a new set of preferable coordinates, thereby suggesting an approach for finding the optimal number of time lags and the embedding dimensions which are the key parameters of this algorithm. The efficacy of this KMPC framework is established by adopting a decentralized frequency control problem through a decoupled synchronous machine system, which we proposed for both the Kundur two-area system as well as the IEEE 39-bus test system.

H∞ Control Design of Power System Based on Generalized Model

The generalized model power system is a complex interconnected system with complex structure and many external disturbance factors, which makes the stability of the system difficult to control. In order to guarantee the stability of the generalized model power system under the condition of external disturbance, more and more effective stability controller design methods are sought. Based on ricarty method and LMI method, the design conditions of H ∞ controller for the generalized power system composed of N subsystems are studied. At the same time, it also provides an effective way and method for analyzing the stability of similar systems.

Optimal IMC-PID controller design for large-scale power systems via EDE algorithm-based model approximation method

In this paper, the authors propose an optimal IMC-PID controller design for the Load Frequency Control (LFC) of large-scale power system via model approximation method. The model approximation method uses the Enhanced Differential Evolution (EDE) algorithm to determine an optimal Reduced Order Model (ROM) for the considered large-scale power system by minimizing the performance measure called Integral Square Error (ISE) between their step responses. Later, the LFC design is carried out using an optimal ROM instead of processing with the large-scale power system model. Thus, this simplifies the design, reduces the computational efforts and also helps in determining the lower order controller. An optimal IMC design methodology is proposed by minimizing ISE between the actual output and the reference input responses of the large-scale power system using EDE algorithm. Further, PID controller gains are acquired by least square model matching with the optimal IMC transfer function. The proposed IMC-PID controller design allows a satisfied reference input tracking performance, robustness in disturbance rejection and improves the dynamic stability of the power system. The proposed method is validated by applying it to a single area power system of third-order SISO model and also extended to a centralized two-area thermal–thermal non-reheated power system of a seventh-order MIMO model. The simulation results and the comparison of error performance indices show the efficacy of the proposed method over the significant methods available in the literature.

A Library of Second-Order Models for Synchronous Machines

This article presents a library of second-order models for synchronous machines that can be utilized in power system dynamic performance analysis and control design. The models have a similar structure to that of the so-called classical model in that they consist of two dynamic states, the power angle and the angular speed. However, unlike the classical model, they find applications beyond first swing stability analysis, i.e., they can be utilized for multi-swing transient stability analysis. The models are developed through a systematic reduction of a nineteenth-order model using singular perturbation techniques. They are validated by comparing their response with that of the high-order model from which they were derived, as well as that of other synchronous machine models existing in the literature, such as the so-called two-axis model and the so-called one-axis model.

Design of power control system for automatic operation of the Kartini reactor

Kartini research reactor which is located at Yogyakarta Indonesia is intended for research, education and training. Students from universities around the city use the reactor for experiments regularly. Regarding the plan of building the first nuclear power plant in Indonesia, the reactor could be improved as the facility of a nuclear power simulator for personnel training of a nuclear power plant. Some improvements on instrumentation and control system were conducted to support the purpose, such as developments of data acquisition of reactor operation parameters, and internet reactor laboratory for remote experiment through the internet connection. However, a power control system for the automatic operation of the reactor is not developed yet. It is important to design an automatic power control for the improvement of the reactor as a simulator of a light-water nuclear power plant. This paper discusses the design of power control of the Kartini reactor based on the Kartini reactor accident and transient code. The control model refers to that of a light water-cooled nuclear power plant. Calculation results show that the control model is applicable to the Kartini reactor. The criterion of SCRAM actuation of the Kartini reactor is satisfied by a small value (0.1) of a control parameter of b. In the future, the control rod simulator which is available in the Kartini reactor might be used to simulate the control system before it is realized to the real reactor.

Integration and Enhancement of Load Frequency Control Design for Diverse Sources Power System via DFIG Based Wind Power Generation and Interonnected via Parallel HVDC/EHVAC Tie-Lines

The present paper discusses the integration as well as contribution of doubly fed induction generator (DFIG) based wind turbines in load frequency control (LFC) of the modern electric power system in order to supply the quality as well as pollution free electric power to the modern customers. In addition the control areas are connected via HVDC tie-line in parallel with EHVAC line with diverse sources i.e. hydro, thermal and gas based power generations in each area. Efforts have been made to propose an optimal LFC design based on the feedback of few state variables which are available for the measurement and contains good information of the complete power system. The LFC design based on few states are implemented and the obtained results are presented to show the LFC enhancement considering DFIG and parallel HVDC/EHVAC lines. Atlast, the beauty and effectiveness of LFC based on few states are compared with LFC design depends on all system states under similar working conditions and the application results are presented.

Frequency-limited pseudo-optimal rational Krylov algorithm for power system reduction

In this paper, a computationally efficient frequency-limited model reduction algorithm is presented for large-scale interconnected power systems. The algorithm generates a reduced order model which not only preserves the electromechanical modes of the original power system but also satisfies a subset of the first-order optimality conditions for H2,ω model reduction problem within the desired frequency interval. The reduced order model accurately captures the oscillatory behavior of the original power system and provides a good time- and frequency-domain accuracy. The proposed algorithm enables fast simulation, analysis, and damping controller design for the original large-scale power system. The efficacy of the proposed algorithm is validated on benchmark power system examples.

A Coordinated Controller Design for DFIG-Based Multi-Machine Power Systems

This paper proposes a novel framework that enables the simultaneous coordination of the controllers of doubly-fed induction generators, synchronous generators, and static compensator devices. The proposed adaptive zero dynamics based approach aims at enhancing the transient stability and improving the voltage regulation of multi-machine power systems under a wide range of operating conditions. The proposed approach was implemented to Kundur's four-machine two-area and the IEEE 39-bus power systems. Its performance was assessed in the presence of various faulty scenarios and disturbances. Eigen-value analysis, time domain simulations, and transient stability margin analysis (measured by critical clearing time) were carried out in the performance assessment. Comparison analysis with other control approaches was also conducted to highlight the effectiveness of the proposed approach. Enhancing the power and voltage stability of large scale multi-machine power systems, damping inter-area power oscillations, and providing faster post-fault recovery time are among the positive features of the proposed approach.

Resilient fixed-order distributed dynamic output feedback load frequency control design for interconnected multi-area power systems

The paper proposes a novel H-&#x221E load frequency control &#x0028 LFC &#x0029 design method for multi-area power systems based on an integral-based non-fragile distributed fixed-order dynamic output feedback &#x0028 DOF &#x0029 tracking-regulator control scheme. To this end, we consider a nonlinear interconnected model for multi-area power systems which also include uncertainties and time-varying communication delays. The design procedure is formulated using semi-definite programming and linear matrix inequality &#x0028 LMI &#x0029 method. The solution of the proposed LMIs returns necessary parameters for the tracking controllers such that the impact of model uncertainty and load disturbances are minimized. The proposed controllers are capable of receiving all or part of subsystems information, whereas the outputs of each controller are local. These controllers are designed such that the resilient stability of the overall closed-loop system is guaranteed. Simulation results are provided to verify the effectiveness of the proposed scheme. Simulation results quantify that the distributed &#x0028 and decentralized &#x0029 controlled system behaves well in presence of large parameter perturbations and random disturbances on the power system.

A novel modified whale optimization algorithm for load frequency controller design of a two-area power system composing of PV grid and thermal generator

This paper proposes a modified approach to the original whale optimization algorithm which is a nature-inspired swarm-based optimization algorithm known as the modified whale optimization (MWOA) algorithm. The superiority of proposed modified algorithm over original algorithm in terms of implementation time and solution quality is compared by taking several benchmark test functions. Further, the real application of the said approach in the engineering field is carried out by designing a PID with derivative (PIDF) controller for frequency regulation of a the most realistic scenario of automatic generation control of a two-area interconnected power system composing of a PV grid and a thermal generator. It is observed that MWOA-based PIDF controller is more effective for the load frequency control compared to conventional PID controller.

Resilient Event-Triggered Output Feedback Control for Load Frequency Control Systems Subject to Cyber Attacks

This paper considers the problem of load frequency control (LFC) design for multi-area power systems. Owing to the multi-area power system with a feature of spatial distribution, it becomes necessary to use the network as a signal transmission medium. The following two problems need to be addressed: 1) the transmission signals transmitted over the communication network are vulnerable to be attacked by adversaries. How to ensure the security of the control system and 2) multi-area power systems have a large amount of data need to be exchanged via the network, how to guarantee the network quality of service and the control performance under the limited network bandwidth. To address these problems, in this paper, a resilient output feedback control strategy in secure means is proposed for LFC systems based on the security criteria. Moreover, a new event triggered mechanism (ETM) is developed, under which the average data releasing rate is much lower than the one using the conventional data transmission mechanism, while it becomes high when the system encounters some external disturbances. To validate the effectiveness of the proposed approach, simulations are performed on a 3-area power system. The results show that the proposed control strategy can maintain the LFC system with a satisfactory control performance in the presence of stochastic cyber-attacks, and the average data releasing rate is of a lower level to save communication and computation resources.

Intelligent power system controller design

In this paper, a type-2 fuzzy-based adaptive sliding mode power system controller is proposed for damping low-frequency oscillations with the aim to enhance power system stability despite model uncertainties introduced by variations of system parameters and external disturbances. Addressing these latter, type-2 fuzzy systems approximating properties are used to approximate unknown power system non-linear dynamics. Furthermore, to achieve more robustness, the proposed controller design is combined with sliding mode approach. The latter and Lyapunov synthesis approach are incorporated in an adaptive fuzzy control scheme such that the derived controller is robust, closely tracking any changes in power system operating conditions and guaranteeing stability while a PI control term is added to mitigate chattering. Proposed stabiliser robustness has been tested on a single machine infinite bus system and a multi-machine power system. Non-linear simulation studies show good performance of the proposed stabiliser and confirm its superiority over conventional PSS and some other types of power stabilisers.

Intelligent power system controller design

In this paper, a type-2 fuzzy-based adaptive sliding mode power system controller is proposed for damping low-frequency oscillations with the aim to enhance power system stability despite model uncertainties introduced by variations of system parameters and external disturbances. Addressing these latter, type-2 fuzzy systems approximating properties are used to approximate unknown power system non-linear dynamics. Furthermore, to achieve more robustness, the proposed controller design is combined with sliding mode approach. The latter and Lyapunov synthesis approach are incorporated in an adaptive fuzzy control scheme such that the derived controller is robust, closely tracking any changes in power system operating conditions and guaranteeing stability while a PI control term is added to mitigate chattering. Proposed stabiliser robustness has been tested on a single machine infinite bus system and a multi-machine power system. Non-linear simulation studies show good performance of the proposed stabiliser and confirm its superiority over conventional PSS and some other types of power stabilisers.

Extended dissipativity-based non-fragile control for multi-area power systems with actuator fault

ABSTRACTThis paper addresses the issue of reliable load frequency control design of an uncertain multi-area power system with constant time delays and disturbances via non-fragile sampled-data control approach. In particular, the parameter uncertainties are assumed to be randomly occurring which are described by the Bernoulli distributed sequences. By constructing a suitable Lyapunov–Krasovskii functional together with Wirtinger-based inequality, a new set of sufficient conditions in terms of linear matrix inequalities is obtained to ensure the asymptotic stability and extended dissipativity of the multi-area power system not only when all actuators are operational, but also in case of some actuator failures. Finally, simulation results are conducted to validate the effectiveness of the proposed control design technique.

A hybrid modified differential evolution-pattern search approach for SSSC based damping controller design under communication constraints

Modern power systems depend greatly on their control systems which operate over communication networks to alleviate the effects of disturbances in the power system. However, it introduces vulnerabilities such as constraints of the communication and control systems that relay precarious control signals. In power systems, damping controllers using feedback signals from remote locations are likely to be adversely affected by communication constraints in future. In this study, an approach is employed to construct the remote control input signal from locally measurable quantity so that the control system performs satisfactorily under communication failure. A hybrid of global search (i.e. differential evolution: DE) and local search (i.e. pattern search: PS) technique is employed for static synchronous series compensator-based damping controller design in Single Machine Infinite Bus and multi-machine power systems. Proposed algorithm is first tested using bench mark test functions and compared with other recent state of art algorithms as well as some other recent variants of DE to validate the efficiency of the proposed approach. It is demonstrated that the proposed methodology provides better damping performance compared to some recently published methodologies.

Control Design and Voltage Stability Analysis of a Droop-Controlled Electrical Power System for More Electric Aircraft

This paper focuses on the analysis of a single dc bus multigenerator electrical power system (EPS) for future more electric aircraft. Within such a single bus paradigm, the paper proposes a detailed control design procedure and provides a stability analysis based on the derivation of the output impedance of the source subsystem and input impedance of the load subsystem, including control dynamics. The single bus characteristic is analyzed and the stability properties of the EPS are investigated when supplying constant power loads. In addition, the paper highlights the impact on stability of the number of parallel sources and of the power sharing ratio. The theoretical analysis is instrumental in designing an optimally stable single dc bus EPS. The key findings are validated by experimental results.

Robust decentralized power system controller design: Integrated approach

Abstract A unique approach to the design of gain scheduled controller (GSC) is presented. The proposed design procedure is based on the Bellman-Lyapunov equation, guaranteed cost and robust stability conditions using the parameter dependent quadratic stability approach. The obtained feasible design procedures for robust GSC design are in the form of BMI with guaranteed convex stability conditions. The obtained design results and their properties are illustrated in the simultaneously design of controllers for simple model (6-order) turbogenerator. The results of the obtained design procedure are a PI automatic voltage regulator (AVR) for synchronous generator, a PI governor controller and a power system stabilizer for excitation system.

Real-Time Adaptive Control of a Fuel Cell/Battery Hybrid Power System With Guaranteed Stability

This paper studies a real-time control problem for a hybrid power system consisting of a proton exchange membrane fuel cell (FC), a unidirectional boost converter, and a lithium-ion battery. An adaptive control strategy is proposed to manage the power sharing in this hybrid power system. System constraints, including the slow dynamics of the FC and the state of charge of the battery, are explicitly considered. The controller achieves tracking a dynamically changing load demand while satisfying the system constraints based on parameter estimations. The main contribution is that, compared with the previous control methods, the proposed control design for hybrid power systems has provable stability and convergence closed-loop properties. Simulation and experimental results are provided to validate the control design.

QFT based Robust Load Frequency Controller Design for Multi-Area Power System

QFT based Robust Load Frequency Controller Design for Multi-Area Power System