An LMI approach to the design of robust delay-dependent overlapping load frequency control of uncertain power systems

This paper considers the design of a fixed structure robust H-infinity Load Frequency Controller (LFC) for an uncertain state-delayed power system. The time-delay, which is due to information transfer over communication links, is assumed to be unknown but upper bounded by a known constant. The uncertainties are parametric and assumed to be norm bounded. The design approach is based on the principle of overlapping decomposition where the tie-line power is modelled as the overlapping variable between the interconnected areas comprising the power system. The design is formulated as a Linear Matrix Inequality (LMI) problem, the solution of which returns a fixed structure delay-dependent robust LFC. The validity of the proposed design approach is demonstrated through simulation studies carried out on an uncertain, state-delayed 2-area interconnected power system. The simulation results clearly illustrate better performance of the proposed robust H-infinity LFC, compared with existing designs. (C) 2016 Elsevier Ltd. All rights reserved.