Improvement of transient stability limit in power system transmission lines using fuzzy control of FACTS devices

The objective of this paper is to investigate the application of FACTS devices to increase the maximum loadability of power transmission lines which may be constrained by a transient stability limit. Hence, the online fuzzy control of superconducting magnetic energy storage (SMES) and static synchronous series compensators (SSSC) are suggested. The fuzzy rule-bases are defined and explained. The validity of the suggested control strategies are confirmed by simulation tests which show that by the use of the proposed method, the line power transfer can be increased via the improvement of the transient stability limit. Finally, the effect of the control loop time delay on the performance of the controller is presented.