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.

Thyristor-Based Facts Controllers for Electrical Transmission Systems

A novel method using particle swarm optimisation (PSO) is proposed for optimising parameters of controllers of a wind turbine (WT) with doubly fed induction generator (DFIG). The PSO algorithm is employed in the proposed parameter tuning method to search for the optimal parameters of controllers and achieve the optimal coordinated control of multiple controllers of WT system. The implementation of the algorithm for optimising the controllers' parameters is described in detail. In the analysis, the generic dynamic model of WT with DFIG and its associated controllers is presented, and the small signal stability model is derived; based on this, an eigenvalue-based objective function is utilised in the PSO-based optimisation algorithm to optimise the controllers' parameters. With the optimised controller parameters, the system stability is improved under both small and large disturbances. Furthermore, the fault ride-through capability of the WT with DFIG can be improved using the optimised controller. Simulations are performed to illustrate the control performance.

Small signal stability analysis and optimal control of a wind turbine with doubly fed induction generator

This paper presents a method that simultaneously tune multiple power system damping controllers using genetic algorithms (GAs). Damping controller structures are assumed to be fixed consisting basically of lead-lag filters. The tuning method takes robustness into consideration as it guarantees system stabilization over a prespecified set of operating conditions. Modified GA operators are used in the simultaneous optimization of both phase compensations and gain settings for the stabilizers. The method is applied for global PSS tuning to the well-known New England system and to the coordinated tuning of 22 PSSs in a 1762-bus modified equivalent South-Southeastern Brazilian system.

Simultaneous tuning of power system damping controllers using genetic algorithms

This paper presents the 15nm FinFET-based Open Cell Library (OCL) and describes the challenges in the methodology while designing a standard cell library for such advanced technology node The 15nm OCL is based on a generic predictive state-of-the-art technology node The proposed cell library is intended to provide access to advanced technology node for universities and other research institutions, in order to design digital integrated circuits and also to develop cell-based design flows, EDA tools and associated algorithms Developing a 15nm standard cell library brings out design challenges which are not present in previous technology nodes Some of these challenges include double-patterning for both metal and poly layers, a very restrictive set of physical design rules, and the demand for lithography-friendly patterns This paper discusses the development of the library considering the challenges associated with advanced technology nodes

Open Cell Library in 15nm FreePDK Technology

The static synchronous series compensator (SSSC) is one of the recently developed flexible AC transmission system (FACTS) controllers. The SSSC coupled with a transformer is connected in series with a transmission line. This paper describes a multicontrol functional model of the SSSC for power flow analysis, which can be used for steady state control of one of the following parameters: (1) the active power flow on the transmission line; (2) the reactive power flow on the transmission line; (3) the voltage at the bus; and (4) the impedance (precisely reactance) of the transmission line. Furthermore, the model can also take into account the voltage and current constraints of the SSSC. The detailed implementation of such a multicontrol functional model in Newton power flow algorithm is presented. A special consideration of the initialization of the variables of the SSSC in power flow analysis is also proposed. Numerical examples on the IEEE 30-bus system, IEEE 118-bus system, and IEEE 300-bus system are used to illustrate the feasibility of the SSSC model and performance of the Newton power flow algorithm.

Advanced modeling of the multicontrol functional static synchronous series compensator (SSSC) in Newton power flow

This paper is devoted to nonlinear dynamic modelling of electric loads. A composite dynamic-static model proposed by P. Ju et.al. (see Control and Decision, vol.4, no.2, p.20-3, 1989) is further developed. This model represents both dynamic and static load characteristics. Meanwhile, it includes the effect of voltage angle on transient active power. The second contribution of this paper is to provide a parameter estimation approach using genetic algorithms. This new approach is proven to be simple yet powerful.

Nonlinear dynamic load modelling: model and parameter estimation

In this paper, a continuation three-phase power flow (CTPFlow) approach in polar coordinates, which can be used to analyze voltage stability of unbalanced three-phase power systems, is proposed. Using CTPFlow, the PV curves of unbalanced three-phase power systems can be obtained. It is found that the patterns of the PV Curves of unbalanced three-phase power systems are quite different from that of balanced three-phase power systems or positive-sequence power systems. The investigations indicate that a CTPFlow is needed where there are unbalanced network or loads existing in a system. Numerical examples are given to illustrate the approach.

Continuation three-phase power flow: a tool for voltage stability analysis of unbalanced three-phase power systems

Usually, it is difficult to use current methods to design a controller with combined continuous and discrete actions. The paper presents a novel approach to solving this problem, i.e. transforming the controller design problem into an optimisation problem and then searching the optimal (or suboptimal) controller parameters by a genetic algorithm. This new approach has been applied to the controller design of a static VAR compensator (SVC) with satisfactory results, which show that the new approach is simple yet powerful.

Genetic algorithm aided controller design with application to SVC

In this paper, general mathematical models for power converter-based FACTS controllers such as STATCOM, SSSC and UPFC suitable for optimal power flow study are established. There are several solution methods for OPF available, which include interior point methods. In this paper, the optimal power flow problem with these converter based FACTS controllers is solved by the newly developed nonlinear interior point methods, since they have been the most successful OPF methods.

http://ieeexplore.ieee.org/iel5/7746/21275/00988418.pdf

E. Handschin

Papers

Nonlinear dynamic load modelling: model and parameter estimation

Continuation three-phase power flow: a tool for voltage stability analysis of unbalanced three-phase power systems

Genetic algorithm aided controller design with application to SVC

Optimal power flow control by converter based FACTS controllers