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

Abstract

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.

A short survey of methods for voltage instability detection

“…In this paper, we do neither discuss the way emergency controls could be initiated from VID, but limit ourselves to outlining the approach proposed in [16] by way of example. This reference suggested to take a snapshot of transmission voltages at the time voltage instability is detected, and use them as threshold voltages in an under-voltage load shedding scheme.…”

“…This reference suggested to take a snapshot of transmission voltages at the time voltage instability is detected, and use them as threshold voltages in an under-voltage load shedding scheme. The latter, which can be centralized as in [16] or distributed as in [11], curtails blocks of load as long as all transmission voltages are not restored above the thresholds received from VID. This scheme is adaptive in the sense that the voltage thresholds are adjusted to the disturbance, but takes advantage of the robustness and closed-loop operation of the load shedding controller(s).…”

State reconstruction from a limited number of synchronized phasor measurements: Application to voltage instability detection

“…Moreover, the formulation that underlies the sensitivity computation [1] can be re-used with little additional effort for other purposes such as identifying the best location for remedial actions [18].…”

“…This section provides illustrative results obtained with the Nordic32 test system previously used in [1], [2], [13], [14], [18]. The one-line diagram of this 52-bus, 20-machine system is shown in Fig.…”

Wide-Area Adaptive Load Shedding Control to Counteract Voltage Instability

“…The continuous development of communication and measurement technologies (most notably Phasor Measurement Units (PMUs)) have opened new perspectives for designing widearea monitoring, detection, protection and control systems (see Phadke and Thorp (2008)), including load shedding control (see Glavic and Van Cutsem (2010)). In this paper we focus on an algorithm that would exploit these new technologies to make undervoltage load shedding adaptive.…”