Power Electronics and Power Systems Antonio J. Conejo Luis Baringo Power System Operations Power Electronics and Power Systems Serieseditors JoeH.Chow,RensselaerPolytechnicInstitute,Troy,NewYork,USA AlexM.Stankovic,TuftsUniversity,Medford,Massachusetts,USA DavidJ.Hill,TheUniversityofHongKong,Pokfulam,HongKong ThePowerElectronicsandPowerSystemsSeriesencompassespowerelectronics, electric power restructuring, and holistic coverage of power systems. The Series comprisesadvancedtextbooks,state-of-the-arttitles,researchmonographs,profes- sional books, and reference works related to the areas of electric power transmis- sion and distribution, energy markets and regulation, electronic devices, electric machines and drives, computational techniques, and power converters and inverters.TheSeriesfeaturesleadinginternationalscholarsandresearcherswithin authored books and edited compilations. All titles are peer reviewed prior to publication to ensure the highest quality content. To inquire about contributing to the Power Electronics and Power Systems Series, please contact Dr. Joe Chow, Administrative Dean of the College of Engineering and Professor of Electrical, Computer and Systems Engineering, Rensselaer Polytechnic Institute, Jonsson Engineering Center, Office 7012, 110 8th Street, Troy, NY USA, 518-276-6374, [email protected]. Moreinformationaboutthisseriesathttp://www.springer.com/series/6403 Antonio J. Conejo • Luis Baringo Power System Operations 123 AntonioJ.Conejo LuisBaringo IntegratedSystemsEngineering ElectricalEngineering ElectricalandComputerEngineering UniversityofCastilla-LaMancha TheOhioStateUniversity CiudadReal,Spain Columbus,Ohio,USA ISSN2196-3185 ISSN2196-3193 (electronic) PowerElectronicsandPowerSystems ISBN978-3-319-69406-1 ISBN978-3-319-69407-8 (eBook) https://doi.org/10.1007/978-3-319-69407-8 LibraryofCongressControlNumber:2017958755 ©SpringerInternationalPublishingAG2018 Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpartof thematerialisconcerned,specificallytherightsoftranslation,reprinting,reuseofillustrations,recitation, broadcasting,reproductiononmicrofilmsorinanyotherphysicalway,andtransmissionorinformation storageandretrieval,electronicadaptation,computersoftware,orbysimilarordissimilarmethodology nowknownorhereafterdeveloped. Theuseofgeneraldescriptivenames,registerednames,trademarks,servicemarks,etc.inthispublication doesnotimply,evenintheabsenceofaspecificstatement,thatsuchnamesareexemptfromtherelevant protectivelawsandregulationsandthereforefreeforgeneraluse. Thepublisher,theauthorsandtheeditorsaresafetoassumethattheadviceandinformationinthisbook arebelievedtobetrueandaccurateatthedateofpublication.Neitherthepublishernortheauthorsor theeditorsgiveawarranty,expressorimplied,withrespecttothematerialcontainedhereinorforany errorsoromissionsthatmayhavebeenmade.Thepublisherremainsneutralwithregardtojurisdictional claimsinpublishedmapsandinstitutionalaffiliations. Printedonacid-freepaper ThisSpringerimprintispublishedbySpringerNature TheregisteredcompanyisSpringerInternationalPublishingAG Theregisteredcompanyaddressis:Gewerbestrasse11,6330Cham,Switzerland Tothememoryofmyfather,Policarpo Conejo,whotaughtmewhyinduction motors rotate. —AntonioJ.Conejo Tomyparents,LuisandSacri. —LuisBaringo Preface Power System Operations provides an introduction to power system modeling, power system steady-state analysis, power system estimation, power system secu- rity,andelectricitymarkets. Specifically, this book covers the analysis of three-phase circuits, the modeling of power system components, the power flow problem, the power system state estimation problem, and the analysis of power system operation security. It also provides an overview of electricity markets, including the unit commitment, the economicdispatch,theself-commitment,andthemarketclearingproblems. The book embodies a problem-solving approach resulting in an up-to-date analysisofthemostimportantproblemsinpowersystemoperations,anditincludes manyillustrativeexamplestoclarifythepowerengineeringconceptscovered. This textbook is intended for advanced undergraduate and graduate teaching in power engineering and other engineering disciplines. It is also useful for industry practitioners since it provides many practical examples developed up to working algorithms. Thisbookconsistsofeightchaptersandtwoappendices. Chapter 1 provides an introduction to power systems, describing its physical, economic, and regulatory layers, as well as the way in which such systems are operated. It also describes how power markets work. Finally, it summarizes the contentsofthebook. Chapter 2 reviews the analysis of three-phase circuits and defines three-phase voltages and currents; three-phase active, reactive, and apparent powers; and the per-unit systems. This chapter provides an appropriate background of three-phase power for the unfamiliar reader, establishing the link between the physical reality and analytical techniques. It can be skipped by readers with knowledge of three- phasecircuitanalysis. Chapter 3 provides steady-state models for the most common components of a powersystem,namely,generators,motors,transformers,lines,andloads. Chapter4addressesthepowerflowproblem,includingnodalequations,admit- tancematrix,powerflowequations,solutiontechniques,andresultanalysis. vii viii Preface Chapter 5 considers the state estimation problem and includes its formulation, solution techniques, observability analysis, and bad measurement detection and identification. Chapter6addressestheformulationandsolutionofoperationsecurityproblems, includingtheoptimalpowerflowandthesecurity-constrainedoptimalpowerflow. Chapter 7 considers a centralized market operation and provides formulation and solution techniques for the unit commitment, the economic dispatch, and the network-constrainedunitcommitmentproblems. Chapter 8 considers a non-centralized market operation and addresses the self- schedulingproblemandtheformulationofmarketclearingalgorithms. Finally, Appendix A reviews the solution to nonlinear systems of equations, whileAppendixBprovidesanintroductiontooptimizationtechniques. Thematerialinthisbookfitstheneedsofanadvancedundergraduateorgraduate courseonpowersystemoperations.Chapters1and2maybeskippedifthestudents arefamiliarwiththeanalysisofpowercircuits.Chapters7and8maybeskippedif theeconomicoperationsofpowersystemsdonotneedtobecovered. Thebookprovidesanadequateblendofengineeringbackgroundandanalytical methods. This feature makes the book of interest to practitioners as well as to students in power engineering and other engineering fields. Practical applications are developed up to working algorithms (coded in GNU Octave and GAMS) that canbereadilyused. The benefits of reading this book include comprehension of power system operationproblems,andlearninghowtoformulatesuchproblems,solvethem,and interpret their solution outputs. This is done using a problem-solving engineering approach. To conclude, we would like to thank our colleagues and students at The Ohio State University and Universidad de Castilla–La Mancha for their insightful observations,pertinentcorrections,andhelpfulcomments. Columbus,Ohio,USA AntonioJ.Conejo CiudadReal,Spain LuisBaringo June2017 Contents 1 PowerSystems................................................................ 1 1.1 Introduction............................................................ 1 1.2 PowerSystemStructure............................................... 1 1.2.1 PhysicalLayer................................................ 1 1.2.2 EconomicLayer.............................................. 5 1.2.3 RegulatoryLayer............................................. 7 1.3 PowerSystemOperations............................................. 9 1.3.1 Day-AheadOperation........................................ 9 1.3.2 HoursBeforePowerDelivery............................... 10 1.3.3 MinutesBeforePowerDelivery............................. 10 1.4 PowerMarkets......................................................... 10 1.4.1 FuturesMarket............................................... 11 1.4.2 Pool........................................................... 11 1.5 ScopeoftheBook ..................................................... 12 1.5.1 WhatWeDo.................................................. 13 1.5.2 WhatWeDoNotDo......................................... 13 1.6 End-of-ChapterExercises............................................. 14 References..................................................................... 14 2 PowerSystemFundamentals:BalancedThree-PhaseCircuits......... 17 2.1 Introduction............................................................ 17 2.2 BalancedThree-PhaseSequences..................................... 18 2.3 BalancedThree-PhaseVoltagesandCurrents........................ 21 2.3.1 BalancedThree-PhaseVoltages............................. 21 2.3.2 BalancedThree-PhaseCurrents............................. 23 2.3.3 EquivalenceWye-Delta...................................... 28 2.3.4 CommonStarConnection................................... 38 2.4 Instantaneous,Active,Reactive,andApparentPower............... 42 2.4.1 Definitions.................................................... 42 2.4.2 HowtoMeasurePower?..................................... 44 2.5 WhyThree-PhasePower?............................................. 44 ix x Contents 2.6 Per-UnitSystem ....................................................... 46 2.6.1 Motivation.................................................... 46 2.6.2 Per-UnitSystemDefinition.................................. 46 2.6.3 DefinitionofBaseValues.................................... 48 2.6.4 Per-UnitAnalysisProcedure ................................ 51 2.7 SummaryandFurtherReading........................................ 52 2.8 End-of-ChapterExercises............................................. 52 References..................................................................... 54 3 PowerSystemComponents:Models....................................... 55 3.1 Introduction............................................................ 55 3.2 GeneratorandMotor .................................................. 56 3.2.1 Three-PhaseGenerator ...................................... 56 3.2.2 Three-PhaseMotor........................................... 57 3.3 PowerTransformer .................................................... 58 3.3.1 Definitions.................................................... 59 3.3.2 ConnectionsofaThree-PhasePowerTransformer......... 61 3.3.3 Per-UnitAnalysis............................................ 66 3.3.4 ModelofaThree-PhasePowerTransformer ............... 67 3.4 Load.................................................................... 68 3.4.1 Constant-ImpedanceLoad................................... 69 3.4.2 InductionMotor.............................................. 69 3.4.3 LoadwithConstantPower .................................. 71 3.4.4 LoadwithConstantVoltage................................. 71 3.5 ElectricalLine ......................................................... 71 3.5.1 EquivalentCircuit............................................ 71 3.5.2 ParametersofElectricalLines............................... 75 3.5.3 EfficiencyandRegulation ................................... 80 3.5.4 ActiveandReactivePowerDecoupling .................... 81 3.6 PowerSystemExamples .............................................. 83 3.7 SummaryandFurtherReading........................................ 94 3.8 End-of-ChapterExercises............................................. 94 References..................................................................... 96 4 PowerFlow ................................................................... 97 4.1 Introduction............................................................ 97 4.2 NodalEquations ....................................................... 98 4.2.1 Two-NodePowerSystem.................................... 98 4.2.2 n-NodePowerSystem ....................................... 100 4.3 AdmittanceMatrix..................................................... 101 4.3.1 Two-NodePowerSystem.................................... 102 4.3.2 n-NodePowerSystem ....................................... 102 4.4 PowerFlowEquations................................................. 104 4.4.1 Two-NodePowerSystem.................................... 104 4.4.2 n-NodePowerSystem ....................................... 107