Control and Automation Systems at the TSO/DSO interface: a survey on the actual functionalities and DSO requirements

The increasing diffusion of variable not programmable energy sources, the forecasted forthcoming diffusion of distributed energy storage systems (ESS) and the active participation of demand will characterize the future Distribution Network in terms of operation and planning. Currently DNOs (Distribution Network Operator) have to assure a secure reliable and good power quality, without taking into consideration any real-time operation of the active components present in their systems. In order to accomplish their missions, DNOs will have to exploit the support of control and automation systems that manage, coordinate and regulate the behaviour of the diverse devices by adopting a true operation of the Distribution Network. Centralized control functions and local control functions will have to coordinate their operation taking into account not only “internal inputs” coming from DNO monitoring and protection systems, but also “external inputs” coming from the Transmission Networks (operated by the Transmission System Operator) and the forthcoming “smart world” (i.e. smart cities, smart transports, smart industries, smart customers etc.). The processing of all such inputs will still have to be subordinated to the possibility for Distribution Companies to operate their network under their ultimate responsibility (DSO – Distribution System Operators). This paper presents an overview of the activities of CIGRE C6.25 Working Group (JWG), focusing on the control and automation systems for the future electric networks. This JWG aims at evaluating the level of automation and control necessary to better manage distribution networks with large penetrations of Distributed Energy Resources (DERs), as
seen from both the TSO and DSO perspectives, and at providing services and information about the two levels of operation (i.e., at TSO and DSO level).