COORDINATION OF EMERGENCY SECONDARY-VOLTAGE CONTROL AND LOAD SHEDDINGTO PREVENT VOLTAGE INSTABILITY

The authors investigate emergency action in terms of secondary-voltage control and the system load shedding for prevention of voltage instab ility. Two modes of co-ordination of these control methods with corres ponding models are proposed, and these are summarised into developed e mergency-control algorithms. The emergency actions of the individual c ontrols and of the proposed co-ordinated control modes are then simula ted on a real multimachine power system. The results so obtaned show t he superiority of the proposed co-ordinated controls over a single con trol action in preventing voltage instability and system breakdown.