Discrete control of series compensation for stability improvement in power systems

Changes in the network such as connecting a shunt resistor, inserting a series capacitor, reducing of generation, load etc., when accomplished under a suitable control scheme can improve transient stability. Switching of series capacitors in a transmission line can also help to damp oscillatory power transients. In this paper a detailed analysis and study of a discrete control strategy for the Thyristor Controlled Series Capacitor (TCSC) to improve stability is presented. A single machine infinite bus system is considered to illustrate the development of the control strategy. The energy function is used in determining the switching instants. The control philosophy is later extended to the multimachine system where the energy of the transmission line is used in determining the control strategy. (C) 1997 Elsevier Science Ltd.