Effect Of Static Var Compensator Research Articles

Traveling wave-based protection for SVC connected transmission lines using game theory

This paper proposes a novel single-end protection scheme for the compensated transmission line based on traveling waves and Game Theory. Initially, this study investigates the effects of Static VAR Compensator (SVC) on Traveling Waves (TW) passing through SVC location. Subsequently, it evaluates the impacts of SVC switching on conventional protections based on traveling wave theory. Following that, a single-end method to locate faults on compensated transmission lines with SVC is presented in this study. Moreover, Game theory was utilized to discriminate extracted TWs in this paper. In order to investigate the sensitivity of the proposed scheme regarding the extraction techniques of TW, two techniques, namely Mathematical Morphology Filter (MMF) and Discrete Wavelet Transform (DWT) have been used to process the signals in this study. The simulation studies using PSCAD software indicate that the proposed protection scheme is reliable and accurate for all possible types of faults on transmission lines with and without SVC. In addition, the proposed technique presents noise immunity.

Enhancement of Voltage Stability by Using SVC for 30-Bus Power System

Voltage stability refers to maintaining the value of the voltage in all busses of the electric network at a steady level (initial operating point) during any sudden disturbance. Voltage instability may happen due to an increase in the demand of the load or in case of any change in the reactive power, thus, the system will go into uncontrollable and unstoppable decline in the voltage level. The effect of Static Var Compensator (SVC) on voltage stability is discussed in the paper, as well as the improvement of the voltage profile. Usually, SVC and FACTS devices were used for enhancing the voltage level profile and so the stability. Choosing the optimal location for the FACTS devices is essential due to its expensive costs. This paper used sensitivity factor to helpful to determine the most correct placement of FACTS devices in the system. Simulations are performed on Kurdistan Region 30-bus Power System using MATLAB-PSAT tool. As a result, the voltage of all 30 buses calculated. Based on the “voltage sensitivity factor”, the nominated weak buses has been marked which are suitable for placing the FACTS devices in order to improve the limits of the voltage stability of the system. Moreover, depending on the obtained optimal locations, a full analysis of the voltage and powers for the system has applied in two cases, before and after placing SVC respectively which is result in notable stability improvement and losses reduction.

Reactive Power Compensation Device Performance Analysis in Fault Recovery of Weak AC System

With the large-scale and large-capacity operation of HVDC transmission, the operating characteristics of the receiving-side power grid have changed significantly. In order to improve the dynamic recovery performance of HVDC transmission system, it is urgent to configure dynamic VAR compensation device in the system inverter Station. In this paper, the PSCAD/EMTDC electromagnetic transient simulation software is used to study the dynamic recovery performance of HVDC system for several different var compensating devices in HVDC inverter. In the case of HVDC inverter station commutation bus short-circuit fault, the effect of static var compensator (SVC), fixed capacitor (FC) and synchronous compensator (SC) on system power recovery is studied. The research results show that fixed capacitors have a certain effect on system fault recovery; SVC can effectively improve the voltage level after the fault but its effect and response speed are not as good as SC, At the same time, a large number of TSC will weaken the strength of the AC system; Synchronous compensator can quickly provide emergency reactive support for the system, accelerate system recovery, and enhance system strength, with obvious advantages.

Enhancement of voltage profile by incorporation of SVC in power system networks by using optimal load flow method in MATLAB/Simulink environments

Flexible AC Transmission Systems (FACTS) controllers could be a suitable alternative to provide reactive power support at the load centers locally and hence keep the voltages within their safe operating limits. Due to high costs of FACTS devices, their proper location in the system must be ascertained. The fundamental object of this thesis work is to improve the voltage profile by reducing the real and reactive power loss in the system. The voltage profile in the system is being improved by using the FACTS device Static VAR Compensator (SVC). In this paper, studies and analyzes SVC technology for voltage enhancement, reducing system losses, suppression of fluctuations. The effectiveness of the proposed method has been tested on IEEE-9 and IEEE-30 bus systems. Optimal placement has been obtained for the base case loading and to verify its locations. To achieves the optimization of the location and the size of the power system to optimize the system performance. A Newton–Raphson Load Flow problem has been formulated with an objective to improve the voltage profile with minimization of the losses. Moreover, the effects of SVC on economic condition have also been investigated. The results obtaining is in the form of the plot and compared with the plots without SVC. This work also helpful for whose persons are working in the field of FACTS controllers planning.

The Modeling of SVC for the Voltage Control in Power System

One of the major causes of voltage instability in power system is the reactive power limit. Therefore, this paper aims to analyze the effect of Static Var Compensator (SVC) on voltage stability of a power system. There are many ways to control the voltage, but in this paper only focus on the SVC and IEEE-9 buses. The SVC circuit and IEEE-9 buses were designed and modelled in Power World. The Newton Raphson method was applied to compute the load flow solution. Then, the reactive power (Q) was injected to SVC and the effect of SVC on IEEE 9-buses were studied. The analysis of voltage control was considered the conditions of fault occurred at the bus. The simulation results obtained in Power World demonstrate that the improvement voltage in the IEEE 9-buses when the Q was injected into SVC circuit. Besides, the QV curve was plotted to show the sensitivity and variation bus voltages with respect to the Q injection.

Application of Static Var Compensator (SVC) With PI Controller for Grid Integration of Wind Farm Using Harmony Search

Abstract Large-scale integration of wind turbine generators (WTGs) may have significant impacts on power system operation with respect to system frequency and bus voltages. This paper studies the effect of Static Var Compensator (SVC) connected to wind energy conversion system (WECS) on voltage profile and the power generated from the induction generator (IG) in wind farm. Also paper presents, a dynamic reactive power compensation using Static Var Compensator (SVC) at the a point of interconnection of wind farm while static compensation (Fixed Capacitor Bank) is unable to prevent voltage collapse. Moreover, this paper shows that using advanced optimization techniques based on artificial intelligence (AI) such as Harmony Search Algorithm (HS) and Self-Adaptive Global Harmony Search Algorithm (SGHS) instead of a Conventional Control Method to tune the parameters of PI controller for SVC and pitch angle. Also paper illustrates that the performance of the system with controllers based on AI is improved under different operating conditions. MATLAB/Simulink based simulation is utilized to demonstrate the application of SVC in wind farm integration. It is also carried out to investigate the enhancement in performance of the WECS achieved with a PI Controller tuned by Harmony Search Algorithm as compared to a Conventional Control Method.

Static Var Compensators & Power System Stabilizers with Adaptive Neuro Fuzzy Controllers in Wind Farms

In the operation of wind farms in power system network, the voltage and power flow control is of primary concern in the efficient operation of the system. Various FACTS controllers are being used nowadays, to improve the system profile during the operation of wind farms. Power system stabilizers are used to damp out the rotor oscillations in the wind farm generator, thus enhancing the stability of the system. This paper investigates initially the effect of Static Var Compensator with conventional PI controllers and conventional Power System Stabilizer on the operation of wind farms. The Static Var Compensator are modified in the proposed work to include Fuzzy based controllers and further with Adaptive Neuro Fuzzy Controllers and their performances are compared in this paper. The conventional Power System Stabilizer in the DFIG based wind farm is also replaced with Fuzzy Stabilizers and Neuro Fuzzy Stabilizers and the effects of these intelligent controllers studied in the system performance. The results confirm that a wind farm in an interconnected power system network exhibits better performance with Adaptive Neuro Fuzzy Controllers for Static Var Compensator & Power System Stabilizers. A greater improvement in voltage profile and power control is obtained using the Hybrid Control technique. MATLAB / Simulink is used to demonstrate the application of Fuzzy and Adaptive Neuro Fuzzy Controllers in Static Var Compensator and Power System Stabilizers.

Effect of Advanced Static VAR Compensator on Control of Power System Load Shedding

This paper investigates the effect of Static VAR Compensator (SVC) on power system load shedding. SVC is mainly used in power system stability improvement. This paper proposes a new use of SVC to reduce load shedding. An algorithm of Newton Raphson method (NR) to reduce the load shedding for installing SVC in the system is proposed in this paper. 5 bus test system example is used to demonstrate the effect on load shedding. The test results show that the effect of SVC is significant, in this Static VAR compensator (SVC) is incorporated in Newton Raphson method in which Power Flow Solution is a solution of the network under steady state conditions subjected to certain constraints under which the system operates. The power flow solution gives the nodal voltages and phase angles given a set of power injections at buses and specified voltages at a few, the model of SVC i.e. SVC Susceptance model is discussed. It is also shown that the power system losses are decreased after incorporating the SVC in this N-R method. The results are generated for 5-Bus system. By incorporating the SVC the amount of load shedding is reduced to get the voltages in their limits.

Analysis of small signal voltage stability in multimachine systems using detailed and reduced formulations

A detailed formulation considering generator swing dynamics for small signal stability analysis of power system is presented. A reduced formulation obtained by decoupling voltage instability from angle instability is derived from the detailed formulation. The accuracy of prediction of voltage instability using the reduced formulation is investigated through the case study of a 10 machine 39 bus system. The effects of exciter gain and time constant are also examined and the results are presented. In addition, the effect of static var compensator (SVC) is also analysed through eigenvalue analysis. The results are also validated by system simulation.

Optimum Firing of SVC's for Normal and Emergency Reactive Power Control

An approach for optimal on-line control strategy of system voltage and reactive power using static VAR compensators (SVC) has been developed. The approach is based on sensitivity relations and linear programming. The simulation of SVC's parameters and firing angle has been presented in the problem of reactive power control in the power system. The article investigates the effect of SVC's on the power system during normal and emergency conditions and determines the different operating modes of SVC's. The choice of SVC's firing angles as control variables in the developed algorithm can be practically implemented for smooth on-line control. Also, the multiple linear objective functions have been considered to be optimized simultaneously and consequently the inherent conflict between them have been overcome. The developed approach is tested on a Word & Hale system to reveal its advantages.

Analysis of the Dynamic Effects of SVC and TCSC Controllers on Preventing Voltage Collapse

The dynamic effects of Static Var Compensator (SVC) and Thyristor-controlled Series Capacitor (TCSC) controllers on preventing voltage collapse are analyzed comprehensively by the small signal method. Hopf bifurcations caused by the interaction between SVC and dynamic load are investigated. The effects of the time constant selections for SVC and TCSC on voltage stability are also discussed. The authors show that TCSC is more effective than SVC in preventing voltage collapse. The steady-state stability limit of system is increased when SVC or TCSC is installed.

Nonlinear analysis of inter-area oscillations: effect of SVC voltage support

Nonlinear modal interaction between system modes is known to contribute to different properties in physical processes. This paper discusses the experience in the use of perturbation theory to study nonlinear system performance in stressed power transmission networks that include multiple flexible a.c. transmission systems controllers. First, an analytical derivation is developed which is used to investigate the effect of static VAR compensators (SVCs) on system nonlinear dynamic behavior. Normal form theory is then applied to study nonlinear modal interaction between SVC control modes and inertial modes. The proposed procedure is demonstrated on the WSCC 4-areas test system. Results of the second-order normal form study are presented and techniques for implementing each phase are discussed.

The Effect of SVC's Elements and Power System's Parameters on Harmonic Magnification: An Experimental Study

Static var compensator (SVC) is used to maintain constant load voltage by compensating the var required by poor power factor loads. The SVC is also used to balance the unbalanced three phase loads. The side effect of the SVC is the generation of harmonic components. Under certain conditions, one of the harmonic components generated by the SVC becomes magnified. This magnified harmonic component leads to a time-bifurcation instability in the thyristor controlled reactors (TCR). This paper shows the effect of the SVCs inductor on harmonic magnification and the time-bifurcation. The experimental results are reported, and the time-bifurcation of the TCR current is generated.

EFFECT OF STATIC VAR COMPENSATOR UPON SYNCHRONIZING TORQUE COEFFICIENT

As power systems have increased in size and complexity, and as the number of power ties between different systems has increased, the nature of the system stability has changed. A static var compensator (SVC), constructed by fixed capacitor (FC) and thyristor controlled reactor (TCR), is designed and implemented to improve the damping of a synchronous generator, as well as controlling the system voltage. The SVC is placed at the generator bus terminal, with the speed and voltage deviation as the feedback signals. In this paper, a formula has been developed showing the effect of SVC upon synchronizing torque coefficient, such that damping is improved and the system voltage is controlled. A simplified analysis of the effect of SVC on the stability of a machine connected to an infinite bus, as well as 21 bus real system is presented. It is observed that the SVC is capable of increasing damping and controlling the system voltage.

Formula for the effect of a static VAr compensator on synchronising torque coefficient

A static VAr compensator (SVC), constructed by a fixed capacitor (FC) and a thyristor controlled reactor (TCR), is designed and implemented to improve the damping of a synchronous generator, as well as controlling the system voltage. The SVC is placed at the generator bus terminal, with the speed and voltage deviation as the feedback signals. In the paper a formula has been developed showing the effect of SVC on synchronising torque coefficient, such that damping is improved and the system voltage is controlled. A simplified analysis of the effect of SVC on the stability of a machine connected to an infinite bus, as well as a simplified 21 bus real system, is presented. Results from digital simulation show that the SVC can greatly enhance the damping of the system oscillation caused by disturbance. Also, the voltage profile of the generator is controlled by the SVC.

Application of static VAr compensators to increase power system damping

A theory for analyzing power system damping enhancement by application of static VAr compensators (SVCs) has been developed using the equal area criterion. Some fundamental issues, such as the effect of SVCs on a power system, how to control an SVC to improve system damping, and the differences between continuous and discontinuous control of SVC reactive power to achieve the maximum damping improvement, are discussed. A discontinuous SVC reactive power output at discrete points is determined from the power deviation on a transmission line. Time-domain simulations of the application of this approach to a one-machine system to increase swing oscillation damping and to a four-machine system to increase the damping of an interarea oscillation mode demonstrate that the theory and method can be applied to solve practical power system damping problems.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Extension of Dynamic Stability Limits: Static VAR Compensation versus Excitation Control

Abstract This paper investigates the effect of static var compensators(svc) on the dynamic stability of an alternator connected to a long transmission line. Frequency response methods are used to assess the closed loop system stability and to define the parameters of a control scheme in accordance with which the svc is controlled to improve the dynamic stability performance of the system. The effect of this form of control on all modes of oscillation including the shaft torsional modes is considered. It is shown that if the VAR consumption of the compensator is controlled in accordance with a terminal voltage signal,the torsional modes of oscillation may be aggravated. However, a scheme incorporating an additional current signal will ensure wider dynamic stability limits and at the same time will improve the damping of the torsional modes. The paper investigates also the compatibility of an excitation control scheme, used to achieve the same goal,and the svc control scheme.