Power System State Estimation Theory and Implementation.pdf

《Power System State Estimation Theory and Implementation.pdf》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。

1、Chapter1IntroductionPowersystemsarecomposedoftransmission,sub-transmission,distributionandgenerationsystems.Transmissionsystemsmaycontainlargenumbersofsubstationswhichareinterconnectedbytransmissionlines,transformers,andotherdevicesforsystemcontrolandprotection.Powermaybeinje

2、ctedintothesystembythegeneratorsorabsorbedfromthesystembytheloadsatthesesubstations.Theoutputvoltagesofgeneratorstypicallydonotexceed30-kV.Hence,transformersareusedtoincreasethevoltagelevelstolevelsrangingfrom69-kVallthewayupto765-kVatthegeneratorterminalsforefficientpowertra

3、nsmission.HighvoltageispreferredatthetransmissionsystemfordifferentreasonsoneofwhichistominimizethecopperlossesthatareproportionaltotheampereRowsalonglines.Atthereceivingend,thetransmissionsystemsareconnectedtothesub-transmissionordistributionsystemswhichareoperatedatlowervol

4、tagelevelsrangingfrom115-KVto4.16-KV.Distributionsystemsaretypicallyconfiguredtooperateinaradialconfiguration,wherefeedersstretchfromdistributionsubstationsandformatreestructurewiththeirrootsatthesubstationandbranchesspreadingoverthedistributionarea.1.1OperatingStatesofaPower

5、SystemTheoperatingconditionsofapowersystematagivenpointintimecanbedeterminedifthenetworkmodelandcomplexphasorvoltagesateverysys-tembusareknown.Sincethesetofcomplexphasorvoltagesfullyspecifiesthesystem,itisreferredtoasthestaticstateofthesystem.Accordingto[1],thesystemmaymovein

6、tooneofthreepossiblestates,namelynormal,emergencyandrestorative,astheoperatingconditionschange.ApowersystemissaidtooperateinanormalstateifalltheloadsinthesystemcanbesuppliedpowerbytheexistinggeneratorswithoutviolatingCopyright2004byMarcelDekker,Inc.AllRightsReserved.anyoperat

7、ionalconstraints.Operationalconstraintsincludethelimitsonthetransmissionlineflows,aswellastheupperandlowerlimitsonbusvoltagemagnitudes.Anormalstateissaidtobesecwreifthesystemcanremaininanormalstatefollowingtheoccurrenceofeachcontingencyfromalistofcriticalcontingencies.Commonc

8、ontingenciesofinterestaretrans-missionlineorgeneratoroutagesduetoune