Preface to the Third EditionSincethe appearance thesecondedition in 1989,the overall energy situation of has changedconsiderably and this has generatedgreat interest innonconventionaland renewableenergy sources,energyconservationandmanagement, power reforms and restructuringanddistributedarrddispersed generation. Chapter t has beentherefore,enlargedand completely rewritten. In addition, theinfluences of environmentalconstraintsare also discussed. Thepresent edition, like the earlier two, is designed for atwo-semester course at the undergraduate level or forfirst-semesterpost-graduate study. Modern power systemshave grownlarger and spreadover larger geographical areawith manyinterconnections betweenneighbouringsystems.Optimalplanning,operationand control of such large-scale systemsrequireadvanced computer-based techniques many of which are explainedinthe student-oriented and reader-friendlymannerby meansofnumericalexamplesthroughout this book. Electric utility engineerswill also be benefittedby the book as it will preparethem moreadequatelyto face the new challenges. The style of writing 'Ihe isamenable self-study. to wide rangeof topicsfacilitates versarileselection of chaptersand sectionsfbr completion in the semestertime frame. Highlights of this edition are the five newchapters.Chapter 13 deals with power system security. Contingencyanalysis and sensitivity factors are described. analyticalframework is developedto control bulk power systems An in sucha waythat securityis enhanced. Everythingseems have a propensity to tofail. Power systemsare no exception.Powersystemsecuritypracticestry to control and operatepower systemsin adefensivepostureso that the effects of theseinevitable failures areminimized. Chapter 14 is an introduction to the use ofstateestimationin electric power systems.We have selectedLeastSquaresEstimationto give basic solution. External systemequivalencing and treatment of bad data are also discussed. Theeconomics of power transmissionhas always lured the planners totransmit as much power as possible through existing transmissionlines. Difficulty of acquiring the right of way for new lines (thecorridor crisis) has always motivated the power engineersto developcompensatorysystems. Therefore, Chapter 15 addresses compensationinpower systems.Both series and shunt compensationof linqs have beenthoroughly discussed. Concepts of SVS, STATCOM and FACTS havc-beenbriefly introduced. Chapter 16 covers the important topic of loadforecasting technique. Knowing load is absolutelyessentialforsolving any power systemproblem. Chapter 17 dealswith the importantproblem of voltagestability.Mathematical formulation, analysis,state-of-art, future trends and challenges are discussed.
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are analysis for MATLAB andSIMULINK, idealprograms powersystemexamples illustrating alongwith 18solved in included thisbookasanappendixtem problems. The help rendered tive theiruse in solvin byShri Sunil Bhat of VNIT, Nagpur in writing this appendix isthankfully acknowledged. Tata McGraw-Hill and the authors wouldlike to thank the following reviewers of this edition: Prof. J.D.Sharma,IIT Roorkee; Prof. S.N. Tiwari, MNNIT Allahabad; Dr. M.R.Mohan, Anna University, Chennai; Prof. M.K. Prof.P.R. Bijwe PEC,Chandigarh; BITS, Pilani; Dr. H.R. Seedhar, Deshmukh, Dr.SanjayRoy, IIT Delhi. and While revising the text, we have had thebenefit of valuable advice and and practising engineerswho usedfrom many professors,students suggestions the earlier editions ofthis book. All these individuals have influenced this to ouredition.We express thanks and appreciation them. We hope thissupport/ would continue in the future also. response D P Kors[m I JNlcn+rn
Preface to the FirstMathematical modellingand solutionon digitalcomputers the only practical is approach to systems analysis andplanning studies for a modern day power system with its large size,complex and integrated nature. The stage has, therefore,beenreachedwhere an undergraduate must be trained in the latesttechniques analysisof large-scale of power systems. similarneedalso exists A in the industry wherea practisingpowersystemengineeris constantly facedwith the challengeof the rapidlyadvancingfield. This book has bedndesignedto fulfil this need byintegratingthe basic principlesof power systemanalysisillustratedthrough the simplestsystemstructurewith analysistechniquespractical size for systems. this book large-scale Insystemanalysisfollows as a naturalextension of thebasicprinciples.The form and level of someof the well-knowntechniques are presented in such a manner that undergraduates caneasily grasp and appreciatethem. The book is designedfor atwo-semester course at the undergraduate level. With a judiciouschoice of advancedtopics, some institutionsmay also frnd it usefulfor a first course for postgraduates. The readeris expectedto havea prior grounding in circuit theory and electrical machines. Heshould also have been exposed to Laplace transform, lineardifferential equations, optimisation techniquesand a first coursein control theory. Matrix analysisis applied throughoutthe book.However, a knowledge of simple matrix operations would suffice andthese are summarisedin an appendixfbr quick reference. The digitalcomputerbeing an indispensable tool for power systemanalysis,computationalalgorithms for various systemstudiessuch as load flow,fault level analysis,stability, etc. have been included atappropriateplacesin the book. It is suggested that wherecomputerfacilities exist, students shouldbe encouraged to buildcomputer programs for these studies using the algorithms provided.Further, the students can be asked to pool the various programs formore advancedand sophisticated studies,e.g. optimal scheduling.importantnovel An featureof the book is the inclusion of thelatestand practicallyuseful topics like unit commitment, generationreliability, optimal thermal scheduling,optimalhydro-thermalschedulingand decoupledload flow in a text which isprimarily meantfor undergraduates. The introductory chaptercontains a discussion on various methods ofelectricalenergygenerationand their techno-economic comparison.glimpse is A given into the future of electricalenergy.The readerisalsoexposed the Indian to power scenariowith facts and figures.Chapters2 and3 give the transmission line parameters theseareincluded and for the sakeof completness the text. Chapter4 on therepresentation power of of gives the steadystatemodelsof thesynchronous systemcomponents machineand the circuit modelsofcompositepower systemsalong with the per unit method.
preface ro rhe Frrst Edition W Chapter5 deals with theperformanceof transmissionlines. The load flow problem isintroducedright at this stagethroughthe simple two-bus systemandbasicconceptsof watt and var control are illustrated.A brieftreatmentof circleconcept of load flow and line compensation. ABCDconstants are generally well covered in the circuit theory courseand are, therefore, relegated to an appendix. Chapter 6 gives powernetwork modelling and load flow analysis, while Chapter 7 givesoptimal system operation with both approximate and rigoroustreatment. Chapter 8 deals with load frequency control wherein bothconventional and modern control approaches have been adopted foranalysis and design. Voltage control is briefly discussed. Chapters9-l l discuss fault studies (abnormal system operation). Thesynchronous machine model for transient studies is heuristicallyintroduced to the reader. Chapter l2 emphasisesthe concepts ofvarious types >1, the above expressionreducesto that of Eq.(3.6)and the error causedby the assumptionof uniformchargedistribution is negligible. (ii) The cross-section both theconductorsis assumed be circular, while of to in actual practicestrandedconductors are used. The use of the radius of thecircumscribingcircle for a strandedconductorcausesinsignificanterror. \4r'
while selecting a large generator,besidesrated MVA and powerfactor, the greatestallowable stator and rotor currents must alsobe consideredas they influence mechanical stresses andtemperaturerise. Such timiting parameters in the operationarebrought out by meansof an operating chart orperformance chart. Forsimplicity of analysis,the saturationeffects,saliency,andresistanceiue ignored and an unsaturated value of synchronousreactanceis considered. Consider Fig. 4.32, the phasor diagram of acylindrical rotor machine. The locus of constantllolx,V) andhenceMVA is a circle centered M. The locus at of constantlEtl(excitation) is also a circle centeredat O. As Mp is proportionalto MVA,QP is proportional to MVAR and Me to MW, all to the samescale which is obtained as follows.
;=;l_*#:,T.":Jff::C = cepacitance/unit length/phaseto neutral /= transmissionline length Z = zl = total series impedance/phase Y =ll = total shunt admittance/phase neutral to Note:Subscript,Sstands a sending-end for quantityand subscriptRstandsfor a receiving-end quantity 5.1 INTRODUCTION 5.2 Thischapter deals primarily with the characteristics and performance oftransmission lines.A problemof major importance power systems theflow in is of load over transmissionlines such that the voltage atvarious nodes is maintained within specified limits. While thisgeneral interconnectedsystem problem will be dealt with in Chapter6, attention is presently focussed on performance of a singletransmissionline so as to give the reader a clear understanding theprinciple involved. of Transmission lines are normally operatedwith a balancedthree-phase load; the analysiscan thereforeproceedona per phasebasis.A transmissionline on a per phasebasis can beregardedas a two-port network, wherein the sendingend voltage Vrand current 15are related to the receiving-endvoltage Vo andcurrent 1o through ABCD constants"as SHORT TRANSMISSION LINE
These constants can be determined easily for short andmedium-length lines by suitable approximations lumping the lineimpedance and shunt admittance. For long lines exact analysis hasto be carried out by considering the distribution of resistance,inductance and capacitance parameters and the ABCD constants of theline are determined therefrom. Equations for power flow on a lineand receiving- and sending-end circle diagrams will also bedeveloped in this chapter so that various types of end conditionscan be handled. *R"f'.. to Appenclix B. 2ff7e9595c
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