BasicPrinciples of Planning VAR Controlon the American Electric PowerSystem

THE STUDYandevaluation ofthegeneration, transmission, andconsumption ofreactive power ina transmission network isasmucha partofpower systemplanning assimilar endeavors inregard toreal power.Asa rule, kilovars aswell as kilowatts needtobeprovided tothecustomer as partofa utility's electric service andtheanalysis ofthetechnically most desirable andeconomically mostattractive way tosupply this reactive power requirement isone ofthesystemplanner's everyday tasks. While thekilowatts canbesupplied onlythrough thedeliberate installation ofan energysourceintheformofa powergenerator, kilovars areautomatically produced, aswell as consumed, bytheelectric network itself. This, ofcourse,results fromtheinherent shunt-capacitive andseries-inductive characteristics ofthehigh-voltage lines. Because ofthis, theplanning ofreactive powersupply isnotonlysubject toagreater rangeof system variables but, inaddition, involves a problem ofcontrol as well as supply. Specifically, an excessofkilovars can often beas muchofa problem as a deficiency. Theeffectiveness of kilovar control on a powersystem notonlyaffects theefficiency ofthesystem's operation andthequality ofitsservice under normal conditions, butalso can beofcrucial importance during majorsystemdisturbances. Wellplanned andcoordinated kilovar control isan indispensable element inthedesign ofa reliable power system.