Coherency identification and construction of dynamic equivalent for large power system

The paper presents a method of identifying coherent generators and for the construction of a dynamic equivalent for a large power system. Coherent groups are identified on the basis of “the equal acceleration and velocity” of the machines in the remote area. The power invariance principle at the machine terminal buses and at the tie buses is followed in the case of equivalent machine representation and network reduction of the coherent groups. The method is applied to 10-M/c, 39-bus and 20-M/c, 118-bus system illustrative examples for several locations