Damping torque analysis of static VAR system controllers
TL;DR: In this paper, the use of damping torque technique to examine the efficacy of various control signals for reactive power modulation of a midpoint-located static VAr system (SVS) in enhancing the power transfer capability of long transmission lines is considered.
Abstract: The use of a damping torque technique to examine the efficacy of various control signals, for reactive power modulation of a midpoint-located static VAr system (SVS) in enhancing the power transfer capability of long transmission lines is considered. A new auxiliary signal, the computed internal frequency (CIF), is proposed which synthesizes the internal voltage frequency of the remote generator from electrical measurements at the SVS bus. It is demonstrated that this signal is far superior to other conventional auxiliary control signals in that it allows full utilization of the network transmission capacity. The damping torque results are correlated with those obtained from eigenvalue analysis. >
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27 Feb 2002
TL;DR: In this paper, the authors present a comparison of different SVC controllers for power transmission networks with respect to their performance in terms of the number of SVC inputs and outputs, as well as the frequency of the SVC outputs.
Abstract: 1. Introduction. 1.1 Background. 1.2 Electrical Transmission Networks. 1.3 Conventional Control Mechanisms. 1.4 Flexible ac Transmission Systems (FACTS). 1.5 Emerging Transmission Networks. 2. Reactor--Power Control in Electrical Power Transmission Systems. 2.1 Reacrive Power. 2.2 Uncompensated Transmission Lines. 2.3 Passive Compensation. 2.4 Summary. 3. Principles of Conventional Reactive--Power Compensators. 3.1 Introduction. 3.2 Synchronous Condensers. 3.3 The Saturated Reactor (SR). 3.4 The Thyristor--Controlled Reactor (TCR). 3.5 The Thyristor--Controlled Transformer (TCT). 3.6 The Fixed Capacitor--Thyristor--Controlled Reactor (FC--TCR). 3.7 The Mechanically Switched Capacitor--Thristor--Controlled Reactor (MSC--TCR). 3.8 The Thyristor--Switched capacitor and Reactor. 3.9 The Thyristor--Switched capacitor--Thyristor--Controlled Reactor (TSC--TCR). 3.10 A Comparison of Different SVCs. 3.11 Summary. 4. SVC Control Components and Models. 4.1 Introduction 4.2 Measurement Systems. 4.3 The Voltage Regulator. 4.4 Gate--Pulse Generation. 4.5 The Synchronizing System. 4.6 Additional Control and Protection Functions. 4.7 Modeling of SVC for Power--System Studies. 4.8 Summary. 5. Conceepts of SVC Voltage Control. 5.1 Introduction 5.2 Voltage Control. 5.3 Effect of Network Resonances on the Controller Response. 5.4 The 2nd Harmonic Interaction Between the SVC and ac Network. 5.5 Application of the SVC to Series--Compensated ac Systems. 5.6 3rd Harmonic Distortion. 5.7 Voltage--Controlled Design Studies. 5.8 Summary. 6. Applications. 6.1 Introduction. 6.2 Increase in Steady--State Power--Transfer Capacity. 6.3 Enhancement of Transient Stability. 6.4 Augmentation of Power--System Damping. 6.5 SVC Mitigation of Subsychronous Resonance (SSR). 6.6 Prevention of Voltage Instability. 6.7 Improvement of HVDC Link Performance. 6.8 Summary. 7. The Thyristor--Controlled SeriesCapacitor (TCSC). 7.1 Series Compensation. 7.2 The TCSC Controller. 7.3 Operation of the TCSC. 7.4 The TSSC. 7.5 Analysis of the TCSC. 7.6 Capability Characteristics. 7.7 Harmonic Performance. 7.8 Losses. 7.9 Response of the TCSC. 7.10 Modeling of the TCSC. 7.11 Summary. 8. TCSC Applications. 8.1 Introduction. 8.2 Open--Loop Control. 8.3 Closed--Loop Control. 8.4 Improvement of the System--Stability Limit. 8.5 Enhancement of System Damping. 8.6 Subsynchronous Resonanace (SSR) Mitigation. 8.7 Voltage--Collapse Prevention. 8.8 TCSC Installations. 8.9 Summary. 9. Coordination of FACTS Controllers. 9.1 Introduction 9.2 Controller Interactions. 9.3 SVC--SVC Interaction. 9.4 SVC--HVDC Interaction. 9.5 SVC--TCSC Interaction. 9.6 TCSC--TCSC Interaction. 9.7 Performance Criteria for Damping--Controller Design. 9.8 Coordination of Multiple Controllers Using Linear--Control Techniques. 9.9 Coordination of Multiple Controllers using Nonlinear--Control Techniques. 9.10 Summary. 10. Emerging FACTS Controllers. 10.1 Introduction. 10.2 The STATCOM. 10.3 THE SSSC. 10.4 The UPFC. 10.5 Comparative Evaluation of Different FACTS Controllers. 10.6 Future Direction of FACTS Technology. 10.7 Summary. Appendix A. Design of an SVC Voltage Regulator. A.1 Study System. A.2 Method of System Gain. A.3 Elgen Value Analysis. A.4 Simulator Studies. A.5 A Comparison of Physical Simulator results With Analytical and Digital Simulator Results Using Linearized Models. Appendix B. Transient--Stability Enhancement in a Midpoint SVC--Compensated SMIB System. Appendix C. Approximate Multimodal decomposition Method for the Design of FACTS Controllers. C.1 Introduction. C.2 Modal Analysis of the ith Swing Mode, C.3 Implications of Different Transfer Functions. C.4 Design of the Damping Controller. Appendix D. FACTS Terms and Definitions. Index.
927 citations
Cites background from "Damping torque analysis of static V..."
...Ratings of up to 345 MVA have been reported in commercial use [12]....
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...A case study of voltage-regulator design for an SVC located at the midline in a single-machine infinite-bus (SMIB) system [12], [13] is presented in Appendix A of this book....
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...[12] IEEE Power Engineering Society/ CIGRE, FACTS Overview, Publication 95TP108, IEEE Press, New York, 1995....
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...4 THE 2ND HARMONIC INTERACTION BETWEEN THE SVC AND AC NETWORK The 2nd harmonic instability [2], [5], [12], [18]–[20] is a major problem experienced by SVCs during events that result in excessive production of 2nd harmonic currents, such as fault clearing, reactor/ transformer switching, operation at significantly high voltage levels, and noise or imbalance in control signals or during severe geomagnetic disturbances....
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01 May 1996
TL;DR: In this paper, a new power system stabilizer (PSS) design for damping power system oscillations focusing on inter-area modes is described, and two global signals are suggested; the tie-line active power and speed difference signals.
Abstract: This paper describes a new power system stabilizer (PSS) design for damping power system oscillations focusing on interarea modes. The input to the PSS consists of two signals. The first signal is mainly to damp the local mode in the area where PSS is located using the generator rotor speed as an input signal. The second is an additional global signal for damping interarea modes. Two global signals are suggested; the tie-line active power and speed difference signals. The choice of PSS location, input signals and tuning is based on modal analysis and frequency response information. These two signals can also be used to enhance damping of interarea modes using SVC located in the middle of the transmission circuit connecting the two oscillating groups. The effectiveness and robustness of the new design are tested on a 19-generator system having characteristics and structure similar to the Western North American grid.
482 citations
Book•
01 Jan 2001
TL;DR: This book discusses the design Principles of Single-Input Single-Output Nonlinear Control Systems and their applications in Electric Power Systems and Nonlinear Excitation Control of Large Synchronous Generators.
Abstract: Preface. 1. Introduction. 2. Basic Concepts of Nonlinear Control Theory. 3. Design Principles of Single-Input Single-Output Nonlinear Control Systems. 4. Design Principles of Multi-Input Multi-Output Nonlinear Control Systems. 5. Basic Mathematical Descriptions for Electric Power Systems. 6. Nonlinear Excitation Control of Large Synchronous Generators. 7. Nonlinear Steam Valving Control. 8. Nonlinear Control of HVDC Systems. 9. Nonlinear Control of Static Var Systems. 10. Nonlinear Robust Control of Power Systems. Index.
248 citations
TL;DR: In this article, a unified model of a power system installed with three flexible AC transmission systems is established, and their effectiveness in suppressing power system oscillations is investigated by analysing their damping torque contributions.
Abstract: The static VAr compensator (SVC), controllable series compensator (CSC) and phase shifter (PS) are three of the options of power electronic devices, referred to as FACTS (flexible AC transmission systems) devices. They are becoming of increasing importance in suppressing power system oscillations and improving system damping. In this paper, a unified model of a power system installed with these three FACTS devices is established. Their effectiveness in suppressing power system oscillations is investigated by analysing their damping torque contributions to the power system. The work in this paper relies on the theoretical analysis of a general single-machine infinite-bus power system where the objective is to present an insight into the operation of the damping control of the FACTS devices.
213 citations
TL;DR: In this paper, a theory for analyzing power system damping enhancement by application of static VAr compensators (SVCs) has been developed using the equal area criterion, where the SVC reactive power output at discrete points is determined from the power deviation on a transmission line.
Abstract: 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. >
188 citations
References
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TL;DR: In this article, the stability of synchronous machines under small perturbations is explored by examining the case of a single machine connected to an infinite bus through external reactance, and the results are shown to be similar to ours.
Abstract: The phenomena of stability of synchronous machines under small perturbations is explored by examining the case of a single machine connected to an infinite bus through external reactance.
1,864 citations
TL;DR: This paper suggests a common nomenclature and control system representation of the various excitation systems now available that can be used to define input data requirements for computer programs, and can provide a consistent format in which manufacturers can respond to requests for excitation system data to be used for system studies.
Abstract: The availability of large digital computers has permitted more extensive computation of power system stability, a subject of increasingly greater importance. This paper suggests a common nomenclature and control system representation of the various excitation systems now available. It can be used to define input data requirements for computer programs, and can provide a consistent format in which manufacturers can respond to requests for excitation system data to be used for system studies.
322 citations
TL;DR: In this paper, the application of static reactive compensators (SVCs) to power transmission systems is discussed, and it is shown that SVCs can provide significant benefits in terms of increased transient stabilty and improved damping for synchronizing power flow oscillations.
Abstract: This paper concerns the application of static reactive compensators (SVCs) to Power transmission systems. Emphasis is placed on stability, and it is shown that SVCs can provide significant benefits in terms of increased transient stabilty liisand improved damping for synchronizing power flow oscillations. The paper includes descriptions Of static VAR compensators, with technical and economic comparisons of different compensators. An SVC system study model is presented which includes provision for modulating reactive compensation in response to a variety of system functions. Study procedures are illustrated which relate sYstem stability objectives to general specifications of SVCs, indluding their locations, regulating slopes, peak reactive power requirements, and modulation control.
86 citations
DOI•
01 Jan 1987TL;DR: In this article, a simplified analysis of the effect of a static reactive-power compensator on the stability of a two-machine system is presented, which shows that the SVC's damping effectiveness is greatly affected by a self-feedback term, whereby a change in SVC suceptance changes the measurement signal which is used to control SVC.
Abstract: A simplified analysis of the effect of a static reactive-power (VAr) compensator (SVC) on the stability of a two-machine system is presented. This analysis shows that the SVC's damping effectiveness is greatly affected by a self-feedback term, whereby a change in SVC suceptance changes the measurement signal which is used to control the SVC. Recognition of this term explains why some control signals are superior to others, and why an SVC might offer limited damping improvement, even with a high-gain damping control. Results of a transient simulation are presented which show that, with a suitable control and a suitable location, an SVC can offer a marked improvement to the damping of rotor-angle oscillations in a power system. The high effectiveness of the SVC in rapidly changing the power flow makes the correct control decision essential during the fault period; guidelines for the control strategy during the fault are presented.
32 citations
01 Jan 1978
28 citations