Identifying the Timing of Controlled Islanding Using a Controlling UEP based Method

The controlled islanding of a power system is a corrective control measure for avoiding cascading and catastrophic power system blackouts. For any given set of islanding boundaries (i.e., how the system should be split), the "timing of controlled islanding" (i.e., the time at which each of the islands should be created) must also be determined. This timing is critical to the success of controlled islanding, since the extreme conditions resulting in islanding include indispensable dynamic behavior. However, prior to the systematic study presented here, this challenging "timing" problem has not been studied in detail. The concept of feasible islanding time interval (FITI) is introduced here as a time interval in which, if controlled islanding is performed for a given boundary, the island's generators will retain their synchronism; thus, the island may reach a new stable equilibrium point. The FITIs are determined using a Controlling Unstable Equilibrium Point (UEP) based method that evaluates the stability of the synchronization of the island to be created. Simulations for different scenarios are performed to validate the effectiveness of the proposed method and explore the characteristics of the FITI and the timing of the controlled islanding.