Static Var Compensator Controller Research Articles

Сравнительный анализ режимов регулирования статического тиристорного компенсатора в системе электроснабжения дуговой сталеплавильной печи высокой мощности

The paper deals with the main results of comparative analysis of static var compensator (SVC) control modes, which are used in electric power system of high and ultra-high power electric arc furnaces (EAF). Traditional SVC control modes designed for implementation of zero reactive power consumption of the steel-smelting complex and voltage stabilization at the common connection point of EAF and SVC are considered. In addition, this paper describes the developed mode, which maintains a constant active power of an electric arc furnace. The effects of supply main parameters and SVC control modes on the EAF electrical characteristics are investigated with a mathematical model of the EAF-120 and SVC-100 MVAr steel-smelting complex developed in the Matlab’s Simulink application. Thus, advantages and disadvantages of the discussed SVC control modes are determined and main recommendations for their application are given.

移動平均制御を用いたSVCによる配電系統の自動電圧制御

Recent years, installation of Photovoltaic (PV) system to power system is active by the environmental problem, feed in tariff system and decrement of initial investment cost. Now, the distribution system is already controlled by the existing voltage controller. However, voltage deviation is caused by high penetration of PV. In order to reduce the effect of PV power fluctuation, the Static Var Compensator (SVC) is planning to install in distribution system. SVC offers a high-speed voltage control. But there is a possibility SVC cannot operate effectively by the difference of a working speed between SVC and existing voltage controllers. So the installation of effectively SVC is required to operate cooperatively with existing voltage controllers. In this research, the automatic voltage control technique of the distribution system by SVC which used the moving average control is proposed. Since the setting value of SVC is updated by the moving average, compared with the conventional SVC control technique, an effective and efficient voltage control is given by the proposed the automatic voltage control technique of SVC.

SVC control enhancement applying self-learning fuzzy algorithm for islanded microgrid

Maintaining voltage stability, within acceptable levels, for islanded Microgrids (MGs) is a challenge due to limited exchange power between generation and loads. This paper proposes an algorithm to enhance the dynamic performance of islanded MGs in presence of load disturbance using Static VAR Compensator (SVC) with Fuzzy Model Reference Learning Controller (FMRLC). The proposed algorithm compensates MG nonlinearity via fuzzy membership functions and inference mechanism imbedded in both controller and inverse model. Hence, MG keeps the desired performance as required at any operating condition. Furthermore, the self-learning capability of the proposed control algorithm compensates for grid parameter’s variation even with inadequate information about load dynamics. A reference model was designed to reject bus voltage disturbance with achievable performance by the proposed fuzzy controller. Three simulations scenarios have been presented to investigate effectiveness of proposed control algorithm in improving steady-state and transient performance of islanded MGs. The first scenario conducted without SVC, second conducted with SVC using PID controller and third conducted using FMRLC algorithm. A comparison for results shows ability of proposed control algorithm to enhance disturbance rejection due to learning process.

Исследование режимов работы статического тиристорного компенсатора при поддержании постоянной мощности дуговой сталеплавильной печи

Исследование режимов работы статического тиристорного компенсатора при поддержании постоянной мощности дуговой сталеплавильной печи

New reactive power calculation method for electric arc furnaces

In this study main reactive power calculation methods are evaluated and compared. Furthermore, a novel simple method that can be used for calculation of reactive power in electric arc furnace (EAF) plants is proposed. The focus here is on their application in the control system of static VAr compensators (SVCs). SVC can compensate only the fundamental harmonic component. So the reactive power signal used in the control system should be sensitive only to the main harmonic component. In addition, the reactive power calculation should be fast enough that SVC can follow the quick changes of the load to mitigate the flicker efficiently. To compare various reactive power calculation methods and to evaluate the proposed method, the simulated known loads are used beside huge amount of practical data recorded in Mobarakeh Steel Company in Isfahan/Iran. Results show the proposed method has the best performance for SVC control system.

Application of Turbine Torsional Oscillation Damping Controller to Static Var Compensator

This paper proposes a new auxiliary turbine torsional oscillation damping controller (TTODC) for static var compensator (SVC) to dampen out subsynchronous oscillations in power systems containing series compensated transmission lines. A new TTODC algorithm on the basis of synchronized phasor measurements received from phasor measurement units (PMUs) is presented. The idea of using remote signals obtained from PMU to dampen subsynchronous resonance (SSR) presented, too. An auxiliary TTODC is proposed for a SVC, using the generator rotor speed deviation signal as the stabilizing and remote signal to dampen subsynchronous oscillations. The performance of the controller is verified in a detailed nonlinear system considering eigenvalue analysis and transient simulations. Sturdiness of the controller is examined by applying the disturbances in the system that causes significant changes in generator's operating point. The IEEE second benchmark (SBM) model is used for the analysis and the SVC is simulated using the power system blockset (PSB) in the matlab/simulink environment.

A Systematic Approach for Optimal Design of SVC Controller to Reduce the Disturbances in Electric Arc Furnace Using Generic Algorithm

Static Var Compensator (SVC) is one of FACTS devices which is used in power systems in order to have a better voltage quality. The fluctuations of voltage and current of the grid connected to electric arc furnace causes power quality problems in the network. SVC, as a fast reactive power control equipment, plays an important role in improving the voltage profile and the transient dynamics of the system arising from the nature of the arc. In this paper the effect of implementing SVC in Mobarakeh Steel Company, for mitigating the voltage transient of power system which is connected to an electric arc furnace, is studied. Then the coefficients of the SVC PI controller are optimized using genetic algorithm and the simulation results are presented.

FACTS Devices Cost Recovery During Congestion Management in Deregulated Electricity Markets

In future electricity markets, flexible alternating current transmission system (FACTS) devices will play key role for providing ancillary services. Since huge cost is involved for the FACTS devices placement in the power system, the cost invested has to be recovered in their life time for the replacement of these devices. The FACTS devices in future electricity markets can act as an ancillary services provider and have to be remunerated. The main contributions of the paper are: (1) investment recovery of FACTS devices during congestion management such as static VAR compensator and unified power flow controller along with thyristor controlled series compensator using non-linear bid curves, (2) the impact of ZIP load model on the FACTS cost recovery of the devices, (3) the comparison of results obtained without ZIP load model for both pool and hybrid market model, (4) secure bilateral transactions incorporation in hybrid market model. An optimal power flow based approach has been developed for maximizing social welfare including FACTS devices cost. The optimal placement of the FACTS devices have been obtained based on maximum social welfare. The results have been obtained for both pool and hybrid electricity market for IEEE 24-bus RTS.

Smooth Evacuation of Power in Grid Connected Small Hydro Power Stations by Application of SVCs

This paper explores some of the practical limitations encountered by small hydro power (SHP) units while evaluating various possibilities so as to maintain continuous generation by these units while ensuring smooth evacuation of every unit of real power generated by such units to the neighboring grid in a grid connected power system scenario. The proposed simulation has been tested under some worst system conditions and case studies conducted on the IEEE 30-bus test system by way of connecting the SHP units to the most critical system bus of the test system with static VAR compensator (SVC) control at the local bus. The test results have been validated with the support of power flow tools on a Matlab based Matpower platform. It is observed that the results obtained through application of SVCs are far more promising than those of the results obtained from OLTC transformer control mechanism only.

Static VAR Compensator Damping Controller Design Based on Flower Pollination Algorithm for a Multi-machine Power System

A new optimization technique known as the flower pollination algorithm is suggested in this article for robust tuning of a static VAR compensator to mitigate power system oscillations. The flower pollination algorithm is based on the properties of flowering plants. The tuning of a static VAR compensator controller is established as an optimization process. The flower pollination algorithm is applied to find out the optimal parameters of a static VAR compensator by diminishing certain performance index. The behavior of the suggested algorithm has been appreciated with the behavior of the genetic algorithm and bacteria foraging to certify the notability of the suggested flower pollination algorithm in designing a static VAR compensator. Simulation results of the flower pollination algorithm based static VAR compensator provide greater attenuation for various loading conditions than the optimized static VAR compensator by genetic algorithm and the optimized static VAR compensator by bacteria foraging. The results of the developed flower pollination algorithm based static VAR compensator are observed via time-domain analysis, eigenvalues, and various indices. Also, the economic value of this work is confirmed.

Improvement of Power System Stability by Optimal SVC Controller Design Using Shuffled Frog-Leaping Algorithm

ABSTRACTThere have been a variety of studies developed to design static Var compensator (SVC) to enhance damping of electromechanical oscillations in power systems. This paper presents a novel method towards an optimal designing of SVC damping controller using shuffled frog-leaping algorithm (SFLA). The optimal parameters of the SVC controller are obtained using SFLA considering different loading conditions. A time-domain objective function is minimized using SFLA to find the optimum controller parameters. The proposed algorithm is implemented on a test system with different loading conditions. The damping characteristics of the presented technique are compared with genetic algorithm (GA) and bacteria foraging optimization algorithm (BFOA) in tuning SVC controller. The comparative analysis demonstrates the superiority of the proposed method on a wide range of operating conditions.

Hybrid electromechanical-electromagnetic simulation to SVC controller based on ADPSS platform

To test the dynamic performance and damping features of a static var compensator (SVC) controller accurately in large-scale interconnected AC/DC hybrid power systems, it is of vital significance to build the detailed electromagnetic transient model. However, it is unrealistic and time-consuming to build the detailed models of all the devices in the actual large-scale power grid. Utilizing the hybrid simulation function in the advanced digital power system simulator (ADPSS) and by dividing the large-scale power grid into the electromagnetic transient sub-grids and electromechanical sub-grids, the computation speed of real-time simulation is remarkably enhanced by the parallel computational capabilities of digital simulator. The SVC controller and the nearby substation are modelled in the electromagnetic transient sub-grid, and the residue sub-networks are modelled in the electromechanical sub-grid. This paper focuses on the mechanism of the hybrid electromechanical and electromagnetic simulation, the detailed modelling and the ADPSS-based digital closed-loop test methodologies of the SVC controller. Eventually, the validity and effectiveness of the modelling and control methods are confirmed by the experimental results.

PSSs and SVC Damping Controllers Design to Mitigate Low Frequency Oscillations Problem in a Multi-machine Power System

This paper deals with the design of multi-machine power system stabilizers (PSSs) and Static var compensator (SVC) using Modified shuffled frog leaping algorithm (MSFLA). The effectiveness of the proposed scheme for optimal setting of the PSSs and SVC controllers has been attended. The PSSs and SVC controllers designing is converted to an optimization problem in which the speed deviations between generators are involved. In order to compare the capability of PSS and SVC, they are designed independently once, and in a coordinated mode once again. The proposed method is applied on a multi-machine power system under different operating conditions and disturbances to confirm the effectiveness of it. The results of tuned PSS controller based on MSFLA (MSFLAPSS) and tuned SVC controller based on MSFLA (MSFLA SVC) are compared with the Strength pareto evolutionary algorithm (SPEA) and Particle swarm optimization (PSO) based optimized PSS and SVC through some performance to reveal its strong performance.

Study on Coordinated Control of Multi-Distribution Static Var Compensator

DFACTS devices can synthetically manage power quality problems. As one of the most DFACTS devices, the coordinated control of multi-distribution static var compensator should be considered. Controllers are separately designed aiming at different functions, that means the controllers are isolated even contradictory. In allusion to the problem that the separately designed DFACTS controllers exist interactions, the paper turns the coordination of the DFACTS controller into multi-objective optimization problem, takes the single-load infinite-bus distribution system with two DSVC as the research object, using the Non-dominated Sorting Genetic Algorithm with elitism approach (NSGA-II) for DFACTS controller parameters optimization, and the simulation results show the effectiveness of the algorithm.

Research on Static Var Compensator Control System Based on SIMATIC - TDC

This paper proposes a new static var compensator control system with SIMATIC-TDC as the master controller and DSP as the auxiliary controller. Siemens TDC is a high-end controller with excellent data processing capacity, which can satisfy the current reactive compensation control algorithm to finish open loop and close loop control. Meanwhile, the programming configuration software is also fully featured, and widely applied in smelting, chemical and power industries. However, the auxiliary controller consisting of DSP and CPLD can quickly finish precise processing of signals (such as high-frequency sampling and signal frequency spectrum analysis). The static var compensation control system consisting of the master controller and the auxiliary controller has now been applied in many projects, achieving sound compensation effect.

Stability improvement of multimachine power system via new coordinated design of PSSs and SVC

In this article, the assessment of new coordinated design of power system stabilizers (PSSs) and static var compensator (SVC) in a multimachine power system via statistical method is proposed. The coordinated design problem of PSSs and SVC over a wide range of loading conditions is handled as an optimization problem. The bacterial swarming optimization (BSO), which synergistically couples the bacterial foraging with the particle swarm optimization (PSO), is used to seek for optimal controllers parameters. By minimizing the proposed objective function, in which the speed deviations between generators are involved; stability performance of the system is enhanced. To compare the capability of PSS and SVC, both are designed independently, and then in a coordinated manner. Simultaneous tuning of the BSO‐based coordinated controller gives robust damping performance over wide range of operating conditions and large disturbance in compare to optimized PSS controller based on BSO (BSOPSS) and optimized SVC controller based on BSO (BSOSVC). Moreover, a statistical T test is executed to validate the robustness of coordinated controller versus uncoordinated one. © 2014 Wiley Periodicals, Inc. Complexity 21: 256–266, 2015

Cost benefit analysis on SVC and UPFC in a dynamic economic dispatch problem

Purpose – The aim of this paper is to compare the performance of static VAR compensator (SVC) and unified power flow controller (UPFC) in dynamic economic dispatch (DED) problem. DED schedules the online generator outputs with the predicted load demands over a certain period so that the electric power system is operated most economically. During last decade, flexible alternating current transmission systems (FACTS) devices are broadly used for maximizing the loadability of existing power system transmission networks. However, based on the literature survey, the performance of SVC and UPFC incorporated in the DED problem and its cost–benefit analysis are not discussed earlier in any of the literature. Design/methodology/approach – Here, the DED problem is solved applying ABC algorithm incorporating SVC and UPFC. The following conditions are investigated with the incorporation of SVC and UPFC into DED problem: the role of SVC and UPFC for improving the power flow and voltage profile and the approximate analysis on cost recovery and payback period with SVC and UPFC in DED problem. Findings – The incorporation of FACTS devices reduces the generation cost and improves the stability of the system. The percentage cost recovered with FACTS devices is estimated approximately using equated monthly installment (EMI) and non-EMI scheme. It is clear from the illustrations that the installation of FACTS devices is profitable after a certain period. Research limitations/implications – In this research work, the generation cost with FACTS devices is only taken into account while calculating the profit. The other benefits like congestion management, cost gained due to land and cost due to stability issues are not considered. For future work, these things can be considered while calculating the benefit. Originality/value – The originality of the work is incorporation of FACTS devices in DED problem and approximate estimation of recovery cost with FACTS devices in DED problem.

A Study on Integrated Performance of Tap-Changing Transformer and SVC in Association with Power System Voltage Stability

Abstract—Electricity market activities and a growing demand for electricity have led to heavily stressed power systems. This requires operation of the networks closer to their stability limits. Power system operation is affected by stability related problems, leading to unpredictable system behavior. Voltage stability refers to the ability of a power system to sustain appropriate voltage levels through large and small disturbances. Steady-state voltage stability is concerned with limits on the existence of steady-state operating points for the network. FACTS devices can be utilized to increase the transmission capacity, the stability margin and dynamic behavior or serve to ensure improved power quality. Their main capabilities are reactive power compensation, voltage control and power flow control. Among the FACTS controllers, Static Var Compensator (SVC) provides fast acting dynamic reactive compensation for voltage support during contingency events. In this paper, voltage stability assessment with appropriate representations of tap-changer transformers and SVC is investigated. Integrating both of these devices is the main topic of this paper. Effect of the presence of tap-changing transformers on static VAR compensator controller parameters and ratings necessary to stabilize load voltages at certain values are highlighted. The interrelation between transformer off nominal tap ratios and the SVC controller gains and droop slopes and the SVC rating are found. P-V curves are constructed to calculate loadability margins.

Robust neural network‐based control of static var compensator

This study addresses the problem of designing robust stabilisation control for a large class of uncertain single-machine infinite-bus electrical power systems with static var compensator (SVC). This class of systems may be perturbed by plant uncertainties, unmodelled perturbations and external disturbances. An adaptive neural network-based dynamic feedback controller is developed such that all the states and signals of the closed-loop system are bounded and the stabilisation error can be made as small as possible. As the small perturbations in the input weighting gains are neglected, an H ∞ control performance can be guaranteed. The adaptive neural network approximation systems are designed to learn the behaviours of the unknown functions, and in turn a modified procedure is proposed such that the number of the neural network basis functions can be significantly reduced. Consequently, the intelligent robust control scheme developed here possesses the properties of computational simplicity and easy implementation from the viewpoint of practical applications. The developed robust control scheme not only can handle a large class of uncertain SVC-driven power systems, but also achieve the aim of enhancing the stability performance. Finally, simulations are provided to demonstrate the effectiveness and performance of the proposed control algorithm.

Coordination between SC and SVC for Voltage Stability Improvement

At any point of time, a power system operating condition should be stable, meeting various operational criteria and it should also be secure in the event of any credible contingency. Present day power systems are being operated closer to their stability limits due to economic and environmental constraints. Maintaining a stable and secure operation of a power system is therefore a very important and challenging issue. Voltage instability has been given much attention by power system researchers and planners in recent years, and is being regarded as one of the major sources of power system insecurity. Voltage instability phenomena are the ones in which the receiving end voltage decreases well below its normal value and does not come back even after setting restoring mechanisms such as VAR compensators, or continues to oscillate for lack of damping against the disturbances. Reactive power limit of power system is one of the major causes of voltage instability. This paper investigates the effects of coordinated series capacitors (SC) with static VAR compensators (SVC) on steady-state voltage stability of a power system. Also, the influence of the presence of series capacitor on static VAR compensator controller parameters and ratings required to stabilize load voltages at certain values are highlighted. Keywords—Static VAR Compensator (SVC), Series Capacitor (SC), voltage stability, reactive power.