PROBABILISTICASSESSMENTOF TRAINSIENTSTABILITY IN A PR\CTICALMULTIM1CFHINE SYSTEM

The application of probabilistic tech- niquesin thequantitative evaluationof power system reliability is steadilyincreasing.Probability methodsare beingusedextensively in the assessment of staticadequacy.Theirapplication to the evaluation of transient or dynamicphenomena has not yet,however, beenwidelyutilized.The probabilistic nature of the transientstabilityproblemand the inclusionof the probabilities associatedwiththe initiating factors suchas the type,locationand clearanceof faultsin theanalysisof a simplesinglemachine-infinitebus systemhasbeendemonstratedin a recentpaper.1 The presentpaper addressesthe problemof trans-ient sta- bilityanalysisin a practical multimachinesystemfrom a probabilistic view-point.The basic conceptsde- velopedin Reference1 are appliedto a simplified 33 busmodelbasedon the SaskatchewanPowerCorporation (SPC)system,to demonstratethetechnique of consider- ingtheprobabilities associatedwiththe occurrence and clearanceof faults. Transientstability indices foreachline,fordifferenttypesof faultsand a singlestabilityindexfor any fault are obtained. A singlestability indexforthe overallsystemis evalu- atedfor.differentfaulttypesand amy faultusing actualsystemoutagestatistics.The effectof fault clearingandreclosing times on the systemstability is investigated forthemost criticallineit1the system.