Delay-independent excitation control for uncertain large power systems using wide-area measurement signals

Technological advance of wide-area measurement systems (WAMS) has enabled the use of a combination of measured information from remote location for transient stability enhancement. However, there exist time delays when remote signals are transported in WAMS. Moreover, the time delays are multiple and uncertain, and depend on the distance, protocol of transmission and several other factors. In order to improve the transient stability of wide-area power system, taking into account the impacts of the time delays and the uncertainties introduced by nonlinearity in system model, a delay-independent decentralized coordinated robust approach is proposed to design excitation controller in terms of H∞ optimization method incorporating linear matrix inequality (LMI) technique based on T-S fuzzy model by using wide-area signals. Simulation demonstrates that the four-machine large system under the robust excitation controller has better transient stability performance in the face of various transmission time delays, severe variations of operating point and faults in various locations.