Coherency Assessment for Intentional Islanding under Different Disturbances

Power networks are susceptible to various types of disturbances, such as faults or sudden changes in load. These disturbances can initiate oscillations between different groups of generators within the system. Accordingly, there is a need to properly perform intentional islanding of specific areas in the power system to prevent widespread blackouts. Specifying coherent generators is a fundamental step for proper controlled islanding. This paper aims to identify the coherent groups of generators under various disturbances. The considered disturbances are three-phase faults at different locations and sudden load changes with different extents. All cases are investigated on the IEEE 39 bus transmission system with the aid of DIgSILENT PowerFactoty as a time-domain simulation platform. Pearson correlation coefficient is adopted to measure the coherence of generators based on their voltage angles. The results demonstrate the viability of this method to determine coherent generators online.