Ch 11 - Generator Protection

Symmetrical Components• Positive Sequence– A set of three phasors that have the same magnitude, are equallydisplaced from each other by 120º, and have the same phasesequence as the system under study (ex ABC)• Negative Sequence– A set of three phasors that have the same magnitude, are equallydisplaced from each other by 120º, and have the opposite phasesequence as the system under study (ex ACB)• Zero Sequence– A set of three phasors of equal magnitude that are all in phase orhave zero displacement from each otherGENERATOR CONTROL AND PROTECTION