Abstract. In this work a non-Lyapunov based approach for estimating the domain of attraction, in the form of a continuation optimization algorithm, is proposed. Accord- ing to the proposed algorithm, the domain of attraction is estimated with nite number of open sets. This method is also applied to design controlling parameters to extend the domain of attraction along desired directions. Simplicity, convergence, capability of estimating domain of attraction for a large class of nonlinear system and ability to demonstrate estimation error for systems with bounded domain of attraction are some advantages of this new approach. Moreover, the directional enlargement of DA is used in order to increase the critical clearing time of power systems for the rst time. The efficiency of the proposed method is veried in simulation results.

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