Decentralized multi-machine power system excitation control using continuous higher-order sliding mode technique

Abstract

A new decentralized continuous higher-order sliding mode (HOSM) excitation control scheme is proposed to enhance transient stability and robustness of multi-machine power system. Power angle deviations are chosen as sliding variables. The HOSM control for uncertain nonlinear multi-machine power system is equivalently transformed into finite time stability problem of uncertain integrator chains. The alleged continuous HOSM excitation controller is composed of geometric homogeneous continuous control and super-twisting second-order sliding mode control law to achieve finite time convergence and overcome power system uncertainties. An adaptive gain, constructed for the super-twisting control item, enables reducing the switching control amplitude of excitation voltage to the minimum possible value along with a finite time convergence. The first-order and second-order time derivatives of power angles are estimated by the exact robust differentiators. Finite time stability of closed-loop power system is strictly proved. Simulation results for a three-machine system and 10-machine 39-bus New England power system demonstrate the effectiveness of the proposed decentralized continuous HOSM excitation control approach.