Control refurbishment principles applied to FACTS controllers

FACTS (flexible AC transmission systems) controllers are now widely available and they demonstrate many years of service experience. Their contribution to the control of a transmission system will become more valuable as the demands and varying applications of the system increase. Of the FACTS controllers in service today, the majority are static VAr compensators (SVCs), of which over 1000 give satisfactory service worldwide. Reviewing the available control packages and the experience of refurbishing an SVC, this paper offers some guidelines on the principles of design for replaceable control components that can deliver a renewable, and therefore ongoing, performance for a FACTS controller.