Abstract
The interaction between the transmission and distribution system operators is mainly based on a unidirectional flow of information (transmission-to-distribution system operators). The resources in the distribution systems are, hence, not utilized fully in overall power system operations, regardless that they may serve as sources of flexibility to manage renewable energy sources fluctuations. In the existing literature, is not very clear how the coordination of the transmission and distribution system operators can and should be modelled. Accordingly, there is limited insights to the potential value coordination may bring to the overall power system operations. As a result, this paper presents a modelling approach for coordination of the transmission and distribution system operators, where flexibility is provided by distributed energy resources located in the distribution systems. Key findings suggest that the total costs of power system operations are reduced when distributed flexible resources are incorporated under a joint coordination framework.