Adaptive wide-area closed-loop undervoltage load shedding using synchronized measurements

Abstract

This paper proposes an emergency load shedding scheme aimed at stopping a developing voltage instability before system disruption. The proposed scheme has a wide-area view of the system, adapts itself to the emergency situation to be handled, and works in closed-loop. It relies on the detection of voltage instability from synchronized measurements recently proposed by the authors. It inherits the assumptions of this detection method (availability of a rich phasor measurement set and communication infrastructure). The method is adaptive in so far as the voltage thresholds used by this undervoltage load shedding scheme are determined from the measurements of the system evolution itself, and the curtailed power is adjusted to the severity of the situation. The features of the proposed scheme are illustrated on a small but realistic system.