A practical method for simplifying the dynamic stability analysis of interconnected power systems

In this paper a practical method for simplifying the analysis of large interconnected power systems is described. The approach is based upon a decomposition scheme which directly exploits the system structure. By analysing and quantifying the strength of connection among generating units, a large power system is decomposed into weakly connected subsystems, each consisting of a group of tightly coupled machines, a common situation in practice. Then the overall system stability is established from the analysis of each decoupled individual subsystem. The method, which can be carried out systematically, saves a considerable amount of storage space and computation time and provides sufficiently accurate results. The procedure is illustrated using a five-machine fifteen-bus system.