双控专业英语.doc

文档介绍：,increaseinloaddemand,orchangeinsystemconditioncausesaprogressiveanduncontrollabledropinvoltage・work・,thegraduallossofsynchronismofmachinesasrotoranglesbetweentwogroupsofmachinesapproachorexceed180°,urswhererotoranglestabilityisnotanissue・Voltageinstabilityisessentiallyalocalphenomenon;however,-・Forpurposeofanalysis,voltagestabilityisusuallyclassifiedintothefollowingtwosubclasses:Large-disturbancevoltagestabilityisconcernedwithasystemsabilitytocontrolvoltagesfollowinglargedisturbancessuchassystemfaults,lossofgeneration,orcircuitcontingencies・-disturbancevoltagestabilityisthat,followingagivendisturbanceandfollowingsystem-controlactions,eptablesteady-statelevels・Small-disturbaneevoltagestabilityisconcernedwithasystem'sabilitytocontrolvoltagesfollowingsmallperturbationssuchasincrementalchangesinsystemload・Thisformofstabilityisdeterminedbythecharact