Optimal Control of Transients in Electrical Power Systems Containing Controlled Reactors Part 2: Optimal Control Problem Solution

This paper studies the optimal control of transient processes in electrical power systems for the purpose of damping the system oscillations arising due to faults. Using a second order nonlinear model of the system, an optimal transient response has been obtained with controlled shunt reactors, which have proved to be effective in improving the transient stability power transfer limit of the system1. A combined control of reactors, excitation and turbine has been applied to a third order nonlinear model of the system and the possibility of coordination between different controls to get optimal transients have been shown. The Pontryagin´s maximum principle has been utilized to formulate the optimization problem and the produced nonlinear two-point boundary value problem was solved using a modified quasilinearization algorithm.