Design of Power System Stabilizers Using Hybrid Differential Evolution

This paper is used to investigate a novel decentralized pole placement design method of lead-lag type power system stabilizers using hybrid differential evolution (HDE). Since the local speed deviations are used as the feedback signals, the stabilizers could be easily implemented. In the design procedures, it wants to place the electromechanical modes within a designated region in the complex variable plane. Participation factors are used to select the sites and number of stabilizers. The HDE method is originally an optimal searching approach. If all electromechanical modes have been moved to the specified region at the convergent steps, the objective function will reach a minimal value. The objective function is chosen to ensure the real parts and/or damping ratios of electromechanical modes. A test power system is used to reveal the goodness of this method. The computation time and convergence characteristic of this approach are better, compared to the differential evolution and genetic algorithm. The coherency measures are also proposed to evaluate the relative behaviors between any pair of generators of the system with and without stabilizers. Key-Words: Power system stabilizer, Electromechanical mode, Pole placement, Hybrid differential evolution, Power system dynamics.