Thispaperdiscussesadistributeddecisionprocedurefordeterminingtheelectricitypriceforareal-timeelectricitymarketinanenergymanagementsystem.ThepricedecisionalgorithmproposedinthispaperderivestheoptimalelectricitypricewhileconsideringtheconstraintsofalinearizedACpowergridmodel.Thealgorithmisbasedonthepowerdemand-supplybalanceandvoltagephasedifferencesinapowergrid.Inordertodeterminetheoptimalpricethatmaximizesthesocialwelfaredistributivelyandtoimprovetheconvergencespeedofthealgorithm,theproposedalgorithmupdatesthepricethroughthealternatingdecisionmakingofmarketparticipants.Inthispaper,weshowtheconvergenceofthepricederivedfromourproposedalgorithm.Furthermore,numericalsimulationresultsshowthattheproposeddynamicpricingmethodologyiseffectiveandthatthereisanimprovementintheconvergencespeed,ascomparedwiththeconventionalmethod.