Coordination of transmission and distribution planning and operations to maximise efficiency in future power systems

Transmission and distribution networks have been historically planned and operated as almost two separate entities. Future power networks will provide a new framework where this practice will no longer be desirable or possible. In particular, achieving maximum efficiency in planning and operating the transmission system will require the consideration, and possible coordination and exchange, of functions, services and information across the transmission-distribution interface. In this paper the authors review current Transmission System Operator (TSO) approaches to planning and operations, present possible visions of future power networks with emphasis on the functions, services and information exchange across the transmission-distribution boundary, and finish with a proposal for reviewing the whole concept of efficiency in future power systems. This work sets the context for research in the area of efficiency of T&D planning and operations with the objective of contributing to the sustainable development of power systems.