Transient Stability of Power Systems

The market liberalization is expected to affect drastically the operation of power systems, which under economical pressure and increasing amount of transactions are being operated much closer to their limits than previously. These changes put the system operators faced with rather different and much more problematic scenarios than in the past. They have now to calculate available transfer capabilities and manage congestion problems in a near on line environment, while operating the transmission system under extremely stressed conditions. This requires highly reliable and efficient software aids, which today are non-existent, or not yet in use. One of the most problematic issues, very much needed but not yet en countered today, is on-line dynamic security assessment and control, enabling the power system to withstand unexpected contingencies without experienc ing voltage or transient instabilities. This monograph is devoted to a unified approach to transient stability assessment and control, called SIngle Machine Equivalent (S1ME).

Klappentext
Transient Stability of Power Systems is a monograph devoted to a hybrid-direct temporal method called SIME (for Single Machine Equivalent). SIME processes temporal information about the multimachine system dynamics to assess and control any type of transient instabilities under any type and model of power systems. Two approaches may be distinguished depending upon the source of information used: Preventative SIME' which relies on a time-domain program to simulate anticipated contingencies, and Emergency SIME' which uses real-time measurements. Preventative SIME mainly comprises two techniques: contingency filtering, ranking, and assessment; and (simultaneous) stabilization of harmful contingencies. The resulting preventative transient stability assessment and control (TSA&e software can be used in all application contexts of transient stability studies. In a control center, for instance, its computational performances enable it to cope with very stringent requirements of real-time operation. Besides, interfacing SIME with an OPF algorithm allows combining transient stability constraints with specifics of the liberalized electricity market. Emergency SIME is a novel closed-loop control technique which contains the transient instabilities caused by contingencies' actual occurrence. It relies on real-time measurements to predict (the size of) instability and, accordingly, to design and trigger control actions able to impede system loss of synchronism. Emergency SIME is particularly suitable for protecting important generation sites and can complement preventative SIME. Both approaches rely on the same principles and basic software which yields a comprehensive and unified approach to TSA&C.The design of near optimal control techniques is a major asset of this software. This book provides extensive illustrations on a variety of power systems ranging from a simple 3-machine test system to real-world power systems comprising up to 627 generators and 4112 busses

Inhalt

1. Chapter 1 - Background.- 1. Introduction.- 2. Security: Definitions and Study Contexts.- 3. Models.- 4. Transient Stability: Time-Domain Approach.- 5. Direct Approaches - An Overview.- 6. Automatic Learning Approaches - A Digest.- 7. Scope of the Book.- 2. Chapter 2 - Introduction to Sime.- 1. Foundations.- 2. General Formulation.- 3. Stability Margins.- 4. SIME's Typical Representations.- 5. Back- and Multi-Swing Phenomena.- 6. Direct Products and Main by-Products.- 7. Preventive vs Emergency SIME.- 3. Chapter 3 - Sensitivity Analysis.- 1. Elements of Sensitivity Analysis.- 2. SIME-Based Sensitivity Analysis.- 3. Compensation Schemes (CSs).- 4. Chapter 4 - Preventive Analysis and Control.- 1. Preliminaries.- 2. Stability Limits.- 3. FILTRA.- 4. Preventive Control.- 5. Chapter 5 - Integrated TSA&C Software.- 1. Integrated Software.- 2. A Case-Study.- 3. TSA&C in Control Centers.- 6. Chapter 6 - Closed-Loop Emergency Control.- 1. Outline of the Method.- 2. Predictive SIME.- 3. Emergency Control.- 4. Simulations.- 5. Discussion.- 7. Chapter 7 - Retrospect and Prospect.- 1. SIME: Hindsight and Foresight.- 2. An Illustration.- 3. Comparing Classes of Methods.- Appendices.- A- The Equal-Area Criterion.- 1. General Concepts.- 1.1 Introduction.- 1.2 Principle.- 1.3 Two-machine system.- 2. Application Example.- B- Data of Simulated Systems.- 1. Three-Machine Test System.- 2. Hydro-Quebec Power System.- 3. EPRI American Test Systems.- 3.1 Test power system C.- 3.2 Test power system A.- 4. Brazilian Power System.- References.