On evaluating the performance of intentional controlled islanding schemes

Intentional Controlled Islanding (ICI) schemes are used to prevent the total system blackouts that can be caused by large system disturbances, or maloperation of protective relays. Since these schemes are designed to operate when the integrity of the system could not be maintained, their development needs to be accompanied by extensive reliability studies to demonstrate that they fulfill the minimum performance requirements. This would ensure their dependable operation when they have to split the network during the cascading events. The possible causes of an ICI failure to operate as designed have to be determined in order to evaluate their reliability. In this paper, an ICI scheme is firstly presented and illustrated using the IEEE 9-bus test system. Next, a generic procedure for assessing the reliability of ICI schemes is discussed. This procedure and its analysis demonstrate the possible sources of ICI incorrect operation and provide the guidelines for estimating the probability of such undesirable events.