Power System Analysis: Short-Circuit Load Flow and Harmonics (Power Engineering (Willis))

844 Pages·2002·13.1 MB·English

by  J.C. Das

Power System
Analysis
Short-Circuit Load Flow and Harmonics
J. C. Das
Amec, Inc.
Atlanta, Georgia
MarcelDekker,Inc. NewYork Basel
•
TM
Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.
ISBN: 0-8247-0737-0
This bookisprintedon acid-freepaper.
Headquarters
Marcel Dekker,Inc.
270Madison Avenue, NewYork, NY 10016
tel: [phone];fax: [phone]
Eastern Hemisphere Distribution
Marcel Dekker AG
Hutgasse 4,Postfach 812,CH-4001 Basel, Switzerland
tel: [phone];fax:[phone]
World WideWeb
http://www.dekker.com
The publisher offers discounts on this book when ordered in bulk quantities. For more
information,writetoSpecialSales/ProfessionalMarketingattheheadquartersaddressabove.
Copyright #2002byMarcel Dekker,Inc. All Rights Reserved.
Neither this book nor any part may be reproduced or transmitted in any form or by any
means,electronicormechanical,includingphotocopying,microfilming,andrecording,orby
any information storage and retrieval system, without permission in writing from the pub-
lisher.
Current printing (last digit):
10 9 8 7 6 5 4 3 2 1
PRINTED INTHE UNITED STATES OFAMERICA
Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.
POWER ENGINEERING
SeriesEditor
H.LeeWillis
ABBInc.
Raleigh,NorthCarolina
AdvisoryEditor
MuhammadH.Rashid
UniversityofWestFlorida
Pensacola,Florida
1. PowerDistributionPlanningReferenceBook,H.LeeWillis
2. TransmissionNetworkProtection:TheoryandPractice,Y.G.Paithankar
3. Electrical Insulation in Power Systems, N. H. Malik, A. A. Al-Arainy, and M. I.
Qureshi
4. ElectricalPowerEquipmentMaintenanceandTesting,PaulGill
5. Protective Relaying: Principles and Applications, Second Edition, J. Lewis
Blackburn
6. Understanding Electric Utilities and De-Regulation, Lorrin Philipson and H. Lee
Willis
7. ElectricalPowerCableEngineering,WilliamA.Thue
8. Electric Systems, Dynamics, and Stability with Artificial Intelligence Applications,
JamesA.MomohandMohamedE.El-Hawary
9. InsulationCoordinationforPowerSystems,AndrewR.Hileman
10. Distributed Power Generation: Planning and Evaluation, H. Lee Willis and
WalterG.Scott
11. ElectricPowerSystemApplicationsofOptimization,JamesA.Momoh
12. Aging Power Delivery Infrastructures, H. Lee Willis, Gregory V. Welch, and
RandallR.Schrieber
13. Restructured Electrical Power Systems: Operation, Trading, and Volatility,
MohammadShahidehpourandMuwaffaqAlomoush
14. ElectricPowerDistributionReliability,RichardE.Brown
15. Computer-AidedPowerSystemAnalysis,RamasamyNatarajan
16. PowerSystemAnalysis:Short-CircuitLoadFlowandHarmonics,J.C.Das
17. PowerTransformers:PrinciplesandApplications,JohnJ.Winders,Jr.
18. Spatial Electric Load Forecasting: Second Edition, Revised and Expanded, H.
LeeWillis
19. DielectricsinElectricFields,GorurG.Raju
ADDITIONALVOLUMESINPREPARATION
Protection Devices and Systems for High-Voltage Applications, Vladimir Gure-
vich
Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.
Series Introduction
Power engineering is the oldest and most traditional of the various areas within
electrical engineering, yet no other facet of modern technology is currently under-
going a more dramatic revolution in both technology and industry structure. But
none of these changes alter the basic complexity of electric power system behavior,
or reduce the challenge that power system engineers have always faced in designing
an economical system that operates as intended and shuts down in a safe and non-
catastrophicmodewhensomethingfailsunexpectedly. Infact,manyoftheongoing
changes in the power industry—deregulation, reduced budgets and staffing levels,
and increasing public and regulatory demand for reliability among them—make
these challenges all the more difficult to overcome.
Therefore, I am particularly delighted to see this latest addition to the Power
Engineeringseries. J.C.Das’sPowerSystemAnalysis:Short-CircuitLoadFlowand
Harmonics provides comprehensive coverage of both theory and practice in the
fundamental areas of power system analysis, including power flow, short-circuit
computations, harmonics, machine modeling, equipment ratings, reactive power
control,andoptimization. Italsoincludesanexcellentreviewofthestandardmatrix
mathematicsandcomputationmethodsofpowersystemanalysis,inareadily-usable
format.
Of particular note, this book discusses both ANSI/IEEE and IEC methods,
guidelines,andproceduresforapplicationsandratings. Overthepastfewyears,my
work as Vice President of Technology and Strategy for ABB’s global consulting
organization has given me an appreciation that the IEC and ANSI standards are
notsomuchinconflictastheyareslightlydifferent butequallyvalidapproaches to
powerengineering. Thereismuchtobelearnedfromeach,andfromthestudyofthe
differences between them.
As the editor of the Power Engineering series, I am proud to include Power
System Analysis among this important group of books. Like all the volumes in the
Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.
iv SeriesIntroduction
PowerEngineeringseries,thisbookprovidesmodernpowertechnologyinacontext
of proven, practical application. It is useful as a reference book as well as for self-
studyandadvancedclassroomuse.Theseriesincludesbookscoveringtheentirefield
of power engineering, in all its specialties and subgenres, all aimed at providing
practicing power engineers with the knowledge and techniques they need to meet
the electric industry’s challenges in the 21st century.
H. Lee Willis
Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.
Preface
Powersystem analysis isfundamentalin the planning, design, and operatingstages,
and its importance cannot be overstated. This book covers the commonly required
short-circuit, load flow, and harmonic analyses. Practical and theoretical aspects
havebeenharmoniouslycombined.Althoughthereistheinevitablecomputersimu-
lation,afeelfortheproceduresandmethodologyisalsoprovided,throughexamples
and problems. Power System Analysis: Short-Circuit Load Flow and Harmonics
shouldbeavaluableadditiontothepowersystemliteratureforpracticingengineers,
those in continuing education, and college students.
Short-circuitanalysesareincludedinchaptersonratingstructuresofbreakers,
current interruption in ac circuits, calculations according to the IEC and ANSI/
IEEE methods, and calculations of short-circuit currents in dc systems.
The load flow analyses cover reactive power flow and control, optimization
techniques, and introduction to FACT controllers, three-phase load flow, and opti-
mal power flow.
The effect of harmonics on power systems is a dynamic and evolving field
(harmonic effects can be experienced at a distance from their source). The book
derivesandcompilesampledataofpracticalinterest,withtheemphasisonharmonic
power flowandharmonicfilterdesign.Generation, effects,limits,andmitigationof
harmonics are discussed, including active and passive filters and new harmonic
mitigating topologies.
The models of major electrical equipment—i.e., transformers, generators,
motors, transmission lines, and power cables—are described in detail. Matrix tech-
niques and symmetrical component transformation form the basis of the analyses.
There are many examples and problems. The references and bibliographies point to
further reading and analyses. Most of the analyses are in the steady state, but
references to transient behavior are included where appropriate.
Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.
vi Preface
A basic knowledge of per unit system, electrical circuits and machinery, and
matrices required, although an overview of matrix techniques is provided in
Appendix A. The style of writing is appropriate for the upper-undergraduate level,
and some sections are at graduate-course level.
PowerSystemsAnalysisisaresultofmylongexperienceasapracticingpower
system engineer in a variety of industries, power plants, and nuclear facilities. Its
unique feature is applications of power system analyses to real-world problems.
I thank ANSI/IEEE for permission to quote from the relevant ANSI/IEEE
standards. The IEEE disclaims any responsibility or liability resulting from the
placement and use in the described manner. I am also grateful to the International
ElectrotechnicalCommission(IEC)forpermissiontousematerialfromtheinterna-
tional standards IEC 60660-1 (1997) and IEC 60909 (1988). All extracts are copy-
rightIECGeneva,Switzerland.Allrightsreserved.FurtherinformationontheIEC,
its international standards, and its role is available at www.iec.ch. IEC takes no
responsibility for and will not assume liability from the reader’s misinterpretation
of the referenced material due to its placement and context in this publication. The
material is reproduced or rewritten with their permission.
Finally, I thank the staff of Marcel Dekker, Inc., and special thanks to Ann
Pulido for her help in the production of this book.
J. C. Das
Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.
Contents
Series Introduction
Preface
1. Short-Circuit Currents and Symmetrical Components
1.1 Nature of Short-Circuit Currents
1.2 Symmetrical Components
1.3 Eigenvalues and Eigenvectors
1.4 Symmetrical Component Transformation
1.5 Clarke Component Transformation
1.6 Characteristics of Symmetrical Components
1.7 Sequence Impedance of Network Components
1.8 Computer Models of Sequence Networks
2. Unsymmetrical Fault Calculations
2.1 Line-to-Ground Fault
2.2 Line-to-Line Fault
2.3 Double Line-to-Ground Fault
2.4 Three-Phase Fault
2.5 Phase Shift in Three-Phase Transformers
2.6 Unsymmetrical Fault Calculations
2.7 System Grounding and Sequence Components
2.8 Open Conductor Faults
Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.
viii Contents
3. Matrix Methods for Network Solutions
3.1 Network Models
3.2 Bus Admittance Matrix
3.3 Bus Impedance Matrix
3.4 Loop Admittance and Impedance Matrices
3.5 Graph Theory
3.6 Bus Admittance and Impedance Matrices by Graph Approach
3.7 Algorithms for Construction of Bus Impedance Matrix
3.8 Short-Circuit Calculations with Bus Impedance Matrix
3.9 Solution of Large Network Equations
4. Current Interruption in AC Networks
4.1 Rheostatic Breaker
4.2 Current-Zero Breaker
4.3 Transient Recovery Voltage
4.4 The Terminal Fault
4.5 The Short-Line Fault
4.6 Interruption of Low Inductive Currents
4.7 Interruption of Capacitive Currents
4.8 Prestrikes in Breakers
4.9 Overvoltages on Energizing High-Voltage Lines
4.10 Out-of-Phase Closing
4.11 Resistance Switching
4.12 Failure Modes of Circuit Breakers
5. Application and Ratings of Circuit Breakers and Fuses According
to ANSI Standards
5.1 Total and Symmetrical Current Rating Basis
5.2 Asymmetrical Ratings
5.3 Voltage Range Factor K
5.4 Capabilities for Ground Faults
5.5 Closing–Latching–Carrying Interrupting Capabilities
5.6 Short-Time Current Carrying Capability
5.7 Service Capability Duty Requirements and Reclosing
Capability
5.8 Capacitance Current Switching
5.9 Line Closing Switching Surge Factor
5.10 Out-of-Phase Switching Current Rating
5.11 Transient Recovery Voltage
5.12 Low-Voltage Circuit Breakers
5.13 Fuses
6. Short-Circuit of Synchronous and Induction Machines
6.1 Reactances of a Synchronous Machine
6.2 Saturation of Reactances
Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.
Contents ix
6.3 Time Constants of Synchronous Machines
6.4 Synchronous Machine Behavior on Terminal Short-Circuit
6.5 Circuit Equations of Unit Machines
6.6 Park’s Transformation
6.7 Park’s Voltage Equation
6.8 Circuit Model of Synchronous Machines
6.9 Calculation Procedure and Examples
6.10 Short-Circuit of an Induction Motor
7. Short-Circuit Calculations According to ANSI Standards
7.1 Types of Calculations
7.2 Impedance Multiplying Factors
7.3 Rotating Machines Model
7.4 Types and Severity of System Short-Circuits
7.5 Calculation Methods
7.6 Network Reduction
7.7 Breaker Duty Calculations
7.8 High X/R Ratios (DC Time Constant Greater than 45ms)
7.9 Calculation Procedure
7.10 Examples of Calculations
7.11 Thirty-Cycle Short-Circuit Currents
7.12 Dynamic Simulation
8. Short-Circuit Calculations According to IEC Standards
8.1 Conceptual and Analytical Differences
8.2 Prefault Voltage
8.3 Far-From-Generator Faults
8.4 Near-to-Generator Faults
8.5 Influence of Motors
8.6 Comparison with ANSI Calculation Procedures
8.7 Examples of Calculations and Comparison with ANSI
Methods
9. Calculations of Short-Circuit Currents in DC Systems
9.1 DC Short-Circuit Current Sources
9.2 Calculation Procedures
9.3 Short-Circuit of a Lead Acid Battery
9.4 DC Motor and Generators
9.5 Short-Circuit Current of a Rectifier
9.6 Short-Circuit of a Charged Capacitor
9.7 Total Short-Circuit Current
9.8 DC Circuit Breakers
10. Load Flow Over Power Transmission Lines
10.1 Power in AC Circuits
Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.