Toward a systems approach to power-electronically switched T&D equipment at value

This paper concerns the difficult problem of dynamic management of T&D controllable equipment. This approach is likely to be necessary in order to ensure reliable operations as the system inputs are becoming very dynamic and hard to predict accurately. Complexity of congestion caused by voltage- and stability-related operating problems will require systematic software tools for managing slow mechanically-switched as well as fast power-electronically-controlled T&D equipment. For the first time sensing and communications technology is available to enable genuine automation of Flexible AC Transmission Systems (FACTS). Systematic design of widely dispersed power-electronically controlled T&D equipment, together with software-enabled on and off line switching and dispatch of set points on mechanically controlled T&D equipment jointly could enable highly efficient and clean utilization in future electric energy systems without endangering system reliability. To the contrary, it is illustrated using small examples in this paper that, unless this approach is implemented, the system may become highly vulnerable during previously unexperienced operating conditions. In addition to the technical challenge underlying systematic dynamic T&D equipment management, major open R&D questions remain concerning the design of protocols for dynamic and interactive risk management by both the T&D owners and operators and the system users themselves.