A Method of Improving Transient Stability by Bang-Bang Control of Tie-Line Reactance

This paper presents a new approach to the problem of improvement of transient stability of a power system by means of optimal control of transients and is in continuation of the work reported in a previous paper.1 Essentially the system state is transferred from that at the beginning of the transient to a post-transient steady state in a nonoscillatory manner by means of a bang-bang control, thereby contributing significantly to the improvement of transient stability. A power system model with two interconnecting tie-lines is considered. It is shown that the control process may be implemented with two intermittent duty series capacitors or a capacitor and a reactor. Results of the synthesis of the optimal controllers and evaluation of realistic indices of performance are presented along with practical considerations.