On the application of the small-gain theorem to the stability analysis of large-scale power systems with delay

The stability analysis of power systems, such as the CIGRÉ 7-machine power system, is hampered by the large size of these systems. Moreover, delays in the local control loops and interconnection delays, caused by the propagation of signals over large distances, further complicate this task. In this paper, it is shown that the small-gain theorem can be used to obtain a tractable solution to the stability analysis problem. An advantage of the proposed approach is that it can guarantee the stability of the power system even when a power plant or tie line fails. The practical applicability of the derived results is illustrated on the CIGRÉ 7-machine power system.