Improvement of power system stability using genetically optimized SVC controller

In this paper, the Authors present the designing of power system stabilizer (PSS) and static var compensator (SVC) based on chaos, particle swarm optimization (PSO) and shuffled frog leaping (SFL) Algorithms has been presented to improve the power system stability. Single machine infinite bus (SMIB) system with SVC located at the terminal of generator has been considered to evaluate the proposed SVC and PSS controllers. The coefficients of PSS and SVC controller have been optimized by Chaos, PSO and SFL algorithms. Fi-nally the system with proposed controllers is simulated for the special disturbance in input power of genera-tor, and then the dynamic responses of generator have been presented. The simulation results show that the system composed with recommended controller has outstanding operation in fast damping of oscillations of power system and describes an application of Chaos, PSO and SFL algorithms to the problem of designing a Lead-Lag controller used in PSS and SVC in power system.

This paper aims to design a nonlinear control scheme for a Static Var Compensator (SVC) in order to improve dynamic stability in a Single Machine Infinite Bus (SMIB) power system. The nonlinear model of the SMIB system is exactly linearized applying feedback linearization method, and the optimal control law is estimated by the Linear Quadratic Regulator (LQR) principle. The performance of the proposed nonlinear controller is compared with the performance of a conventional controller whose parameters are optimized through Genetic Algorithm (GA). The results and effectiveness of the proposed control schemes are presented employing time domain simulation and analysis. It has been observed that, in comparison with the conventional controller, significant improvements in dynamic stability of the test power system are achieved by the proposed nonlinear control strategy.

This research evaluates the viability of the artificial eco-system optimization (AEO), a novel metaheuristic algorithm, for optimal power system stabilizers (PSSs) tuning in single-machine infinite bus (SMIB) and western system coordinating council (WSCC) multi-machine power systems. The PSS design problem was converted to an optimization problem to achieve optimal tuning, and an eigenvalue-based objective function was employed. The eigenvalue objective function was defined to optimally obtain the PSSs parameters and enhance the power system dynamic performance by improving the damping of electromechanical modes (EMs). The proposed AEO-based PSS performance was validated by comparing the results obtained with genetic algorithm (GA)-based PSS, particle swarm optimization (PSO)- based PSS design, and similar published work. AEO-based PSS method of tuning has been shown to damp electromechanical modes (EMs), control low-frequency oscillations (LFO), and provide better transient performance and convergence rate. Cite this article as: T. Ebuka Odoh, A. Sabo, N. Izzri Abdul Wahab and H. Beiranvand, "Artificial eco-system-based optimization algorithm for optimal design of single-machine infinite bus power system stabilizer," Electrica, 23(3), 522-533, 2023.

This paper studies the control strategies for enhancing the transient stability of a single machine infinite bus (SMIB) power system. First, the dynamical SMIB model is established, and the excitation control is discussed. Next, the damping linear optimal excitation controller (DLOEC) and the output feedback H_infinity control strategy are studied. Then, the DLOEC and the suboptimum H_infinity controller are designed for a specific SMIB power system. The effectiveness of the two presented methods is verified by simulations. The simulation results show that the presented methods improve the transient stability of the SMIB power system and that the H_infinity controller provides better performance than the DLOEC controller.

Enhancing voltage stability and LVRT capability of a wind-integrated power system using a fuzzy-based SVC

A new algorithm simulating the impacts of the VAR supporting devices such as the static var compensators (SVCs) and the synchronous condensers (SCs) under condition of symmetrical disturbances in multi-machine power system is mentioned. Some typical numerical examples are presented in this article.
 The comparisons of variation of the state parameters, such as the voltage, frequency, reactive power outputs and asynchronous torques…are simulated under condition of the action of the automatic voltage regulation systems of generators and of the VAR supporting devices.
 The transient energy margins are calculated and compared to assess the transient stability in multi-machine power system. Basing on this algorithm, the PC program uses the elements of the eigen-image matrix to bring the specific advantages for the simulation of the transient features of state variables.

The dynamic stability improvement of a longitudinal power system using a power system stabilizer (PSS) and a static VAr (reactive volt-ampere) compensator (SVC) is reported. An analytical approach is developed for the determination of PSS parameters. The effect of static VAr compensators installed at several different locations along 345 kV trunk lines on system responses is examined. Results from time-domain simulations indicate that the PSS and the SVC are very effective in damping system oscillations. >

The coordinated control for SVC and generic/multi-band PSS for power swing damping is presented for the multimachine power system. The background and the mathematical models of the generic PSS, the multi-band PSS and the SVC are presented. The V-I characteristics as well as the dynamic properties of the static var compensator (SVC) are presented. The multi-machine power system is simulated using MATLAB and the effect of PSS and SVC on dynamic response of the system under single-phase fault and three-phase fault are simulated. The simulation results reveal that the coordinated control of the SVC and the generic/multi-band PSS is an effective solution to damp low frequency oscillation for multimachine power system and enhance global stability of the large inter-connected power system.

<span>This paper presents the capability of a fuzzy logic based stabilizer used for generating the supplementary control signal to voltage regulator of static VAR compensator (SVC) for improving damping oscillations in power systems. Generator speed deviation and line active power were chosen as input signals for the fuzzy logic controller (FLC). The quantity of reactive power supplied/absorbed by SVC is determined based on the two input signal and deviation of terminal voltage at each sampling time. The effectiveness and feasibility of the proposed control is demonstrated with Single Machine Infinite Bus (SMIB) system and multi machine system which show improvement over the use of a fixed parameter controller. It has been observed that a robust controller is obtained with fuzzy logic controller.</span>

This paper represents, the enhancement of power system stability by coordinating control design of power system stabilizer (PSS) and static synchronous series compensator (SSSC). The coordinated controller's parameters are formulated as an optimization problem and to search for such optimal parameters firefly (FF) algorithm is used in both cases of single machine infinite bus and multi machine power system(MMPS). The coordinately control design of power system stabilizer and PID based SSSC based controller uses speed deviation as input signal. The dynamic performance of the proposed technique is obtained under different loading conditions and different position of fault conditions. The effectiveness and robustness of coordinated design approach is discussed to improve the damping of power system oscillation and hence stability of power system.

The objective of this paper is to consider the use of Thyristor Control Series Compensator (TCSC) to advance the stability of a Single Machine Infinite Bus (SMIB) power system. The modern GSA optimization is applied on this model to find out the optimal controller parameters. The dynamic performance of GSA based TCSC controller is analyzed under different disturbances, loading conditions and parameter variations.

By gain-scheduled controller parameterizing according to phase plane partitioning, swing equations for individual synchronous generators in multi-machine power systems are approximated through sequential linear time-invariant (LTI) models, based on which we formulate a pseudo H 2 -performance control via static VAR compensators (SVC) for stabilizing generators and improving their transient and steady-state behaviors. SVC belongs to the flexible ac transmission systems, which are widely utilized for reactive power compensation and stabilization in power systems. The pseudo H 2 -performance control is addressed by the H 2 -performance optimization techniques for LTI systems but in the gain-scheduled sense. Numeric examples illustrate efficacy of the suggested stabilization and performance improvement.

Power-system stability improvement by a static synchronous series compensator SSSC-based damping controller is thoroughly investigated in this paper. The present study considered both local and remote signals with associated time delays. The design problem of the proposed controller is formulated as an optimisation problem, and gravitational search algorithm GSA is employed to search for the optimal controller parameters. The performances of the proposed controllers are evaluated under different disturbances for both single-machine infinite bus power system and multi-machine power system. The performance of the proposed controllers with variations in the signal transmission delays has also been investigated. Simulation results are presented under various operating conditions and disturbances to show the effectiveness and robustness of the proposed approach.

In a deregulated power system uncertainty exists and lack of sufficient damping can lead to Low Frequency Oscillations (LFO). The problem can be addressed using robust Power System Stabilizers (PSS). In this paper, an optimal procedure to design a robust PID-PSS using interval arithmetic for the Single Machine Infinite Bus (SMIB) power system is proposed. The interval modelling captures the wide variations of operating conditions in bounds of system coefficients. In the proposed design procedure, simple and new closed loop stability conditions for an SMIB interval system are developed and are used to design an optimum PID-PSS for improving the performance of an SMIB system. The optimum PID-PSS is attained by tuning the parameters using the FMINCON tool provided in MATLAB. The robustness of the proposed PID-PSS design is validated and compared to other notable methods in the literature when the system is subjected to different uncertainties. The simulation results and performance error values show the effectiveness of the proposed robust PID-PSS controller.

In this paper an Optimization based linear control design method is used to achieve a coordinated design of Power System Stabilizer (PSS) and Thyristor Controlled Series Capacitor (TCSC) for power system damping improvement with pre specified control design requirements. The settling time is considered as main performance criteria in time domain specification and gain and phase margins for frequency domain specifications. The main objective of the coordination of controllers is to improve the global stability through damping of oscillations by improving the damping ratio of the system and minimizing the settling time of the system response. Thus coordination increases the reliability of the system and maintains the required damping even one or more controllers are out of service and hence reduces the need for additional controller. Optimization based linear control design is used to determine the optimal gain and time constant setting of lead-lag controller parameters for PSS and TCSC. The coordinated PSS and TCSC controller is tested in the Single Machine Infinite Bus Power System (SMIB). Simulation is carried out using Matlab2011b. From the time domain simulation results it is observed that oscillations are damped out, settling time is reduced and damping ratio is improved. From bode plot it is inferred that gain and phase margin of the system is further improved to satisfy the system requirements. In the overall analysis, optimization based linear control design implemented for the coordination of PSS and TCSC controller satisfies the practical requirements of the power system oscillation damping problem, also shift the eigen values to the left half of the s-plane as far as possible and hence enhances the overall system stability