Tracing generator coherency indices using the continuation method: a novel approach

Slow coherency-based generator grouping in power systems is primarily dependent on the participation of generators in the slow modes. In the literature, generator coherency has been typically obtained at a specific operating point. This paper presents a new approach using the continuation method to trace the loci of the coherency indices of the slow modes in the system with respect to variation in system conditions to obtain the updated coherency information between generators. The approach has been applied to a 10-generator 39-bus New England system, and a 29-generator 179-bus model of the WECC system and the impact of load variation on generator coherency indices has been investigated.