SQUARESALOGORITHM
Theobservationequationofpowersystemstateestimationisnonlinearandcanbelinearas:
z=Hx+v(1)
wherexisandimensionstatevector;zisamdimen-sionmeasurementvector;visameasurementerrorvector,whichisnormalizedas:Hisam×ndimensionobservationmatrix.Rank[H]=n.Itselementsaredecidedbythestructureofpowersystemandtheconfigurationofmeteringsystem.Ingeneralcase,Hcanactasconstantbe-causeitschangeisminuteineveryiteration.
Theobservationfunctionapplyingweightedleastsquaresalgorithmis:
whereR-1isweight,Δzisthedifferencebetweenthemeasurementandthevalueofthecorrespondingmeasurementfunction.Eq.(2)isexpressedinavec-
torform:
3 THEREALIZATIONOFRLSALGO-RITHMUSINGANEURALNETWORK
Accordingtothereference[3]thataenergyelectroniccircuitcouldrealizeitscircuitmodel.Inreference[1],thereisanetworkthatcomprisedofamainandasub-sidiarynetwork,showedastheFigure1.Thepaperappliesthenetworktopowersystemstateestima-tionsuccessfully.Themainandthesubsidiaryneu-ronsareconnectedwitheachother.Theleftmainnetworkhasnneurons,everyneuronismodeLEDasanamplifier,andtherelationofitsinputandoutputisnonlinear.IthasinputcapacitanceCiandresis-tanceRi.vi(t)andui(t)arethei-thneuronoutputandinputvoltage.g(u)isadegressivefunction.
Therightsubsidiarynetworkhasmneurons,itsrela-tionbetweenoutputandinputisf(z).Theoutputvoltageofi-thneuronisqi(t).Theweightbetweenthei-thneuroninthesubsidiarynetworkandthej-thneuroninthemainnetworkisBij,MatrixB=(Bij)istheweightedmatrix.R0=(r1,r2,…,rm)Tisadeviationelectriccurrentvector.Wealsocanconcludeformthetable1thattheoutputinmainnetworkistheinputinsubsidiaryandtheinputinmainnetworkistheoutputinsubsidiary.
AccordingtoKirchhoffvolatileandcurrentlaw,everyneuroninmainnetworkhastheequa-tion:
Inordertoguaranteethestabilityofthenet-workandtheenergyfunctionisusuallycomposedoftheobservationfunctionwhichreflectstheoptimiza-tionquestionandseveralrestrictivefactors.ThenLyapunovfunctionisdefinedas:
whereF(·)isf(z)variableintegral.Selectproperlytheformatf(z)andg(u)andthenetworkisstableandtheminimumoftheenergyfunctioncanbegot-ten.InordertogetthekeyofRLS,weselect
Δxistheoutputofthemainnetwork,Yisdevi-ationelectriccurrent,uistheinputofthemainnet-work.TheseareintroducedintoEq.(8),
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