This paper addresses a new decentralized robust load-frequency control (LFC) design in a multi-area power system under deregulation based on bilateral policy scheme. In each control area, the effect of bilateral contracts is taken into account as a set of new input signals to modify the traditional LFC structure. The LFC problem is considered as a multi objective control problem and formulated via a mixed H2/H ∞ control technique, then it is easily carried out to synthesis the desired low-order robust controllers by solving standard linear matrix inequalities (LMI). A three-area power system example with possible contract scenarios and a wide range of load changes is given to illustrate the developed approach. The results of the proposed multi-objective control strategy are compared with pure H ∞ design. The resulting controllers are shown to maintain the robust performance and minimize the effect of disturbances and specified uncertainties.
