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1、ReferenceProtectionHandbookCHAPTER1ThePrinciplesofPower-networkCalculationsByC.H.LACKEY.INTRODUCTIONpointinthecircuittowhichthevoltageisrelated.Eahthereforemeansthevoltageofphase-arelativetoTheuseofcalculator-boardsfortheevaluationofnet•phase-b;Eanmeansthevoltageofphase-ar
2、elativetoworkcurrentsandvoltagesisestablishedpractice,andneutral-noItisessential,ifconfusionistobeavoided,resultsinagreatsavingoftimeascomparedwithdirectthatthenomenclaturedecideduponshallbemostcalculation.Themanipulationofacalculator-boardmayrigorouslyapplied.Ifthisisdone
3、,interphase-voltage•notdemandgreatskillonthepartoftheoperator,orvectors,whichsometimesgivetrouble,becomequiterequireafullknowledgeoftheprinciplesinvolved,butsimple.Therearesixforthethreephases,namelyE.abtheinterpretationoftheresultsandafullrealisationofandEba,EbcandEcb,Eca
4、andEac;andtheseareshownInthenatureoftheproblemtobesolvedanditsfig.2.implicationsdorequireasoundknowledgeofthebasicprinciplesofcalculation.Apartfromthis,acalculator-boardisoftennotavailable,ortheproblemmaybesimpleenoughfordirectsolution.Engineersassociatedwiththedesignandpe
5、rformanceofpower-supplysystemsshouldsoequipthemselvesastobeabletopredictcurrentandvoltagevaluesunderbothnormalandabnormalconditions:aclearunderstandingfen-ofthebasicprinciplesoffault-calculationsisofpara•mountimportanceinthisconnection.Attentionisdevotedheremainlytotheprin
6、ciplesoffault•calculation,butitshouldbeunderstoodthatmanyofthe-----E""principles,suchasthoseofvector-algebraandnetwork•reduction,areequallyapplicabletoload-studies.Fault-calculationshavecometoberegardedastheprerogativeofexperts,andasoperationsrequiringratherexceptionalski
7、ll.ExperienceiswithoutadoubtaEbnnecessaryadjuncttospeed,butnogreatskillormathematicalabilityisnecessaryfortheproperunderstandingandsolutionofmostproblems.Thesubjectwillbeconsideredunderthefollowingfour-headings:Vector-Representation.Vector-AlgebraandImpedance-Notations.Net
8、work-ReductionandtheCalculationofE'a+---
