TDX-Assist: Beyond state of art in TSO-DSO interoperability – The Portuguese demonstrator

Abstract

The TSO-DSO relationship is a key topic in the operation of the electricity market and is even more crucial as Europe paves its way into the constitution of a European energy market ranging from Transmission to Distribution. Following this, the subject addressed in this paper is an overview of the TDX-Assist project with a focus on the Portuguese demonstrator, which has the participation of EDPD (Portuguese DSO), INESC TEC, Nester and REN (Portuguese TSO). This project, being developed under European Union’s Horizon 2020 R&I program, aims to design and develop novel ICT tools that facilitate scalable and secure information systems and data exchange between TSO and DSO. The continuous shift from TSO connected generation to DSO connection generation is presenting new challenges to DSOs and TSOs. Keeping the system up and running in the future requires a more collaborative approach to the issue of DSO/TSO cooperation that traditionally existed in the vertically integrated network paradigm. It is possible to use IT tools to make sure both system operators have the relevant information they require to fulfil their mission. TDX-Assist’s Portuguese demo helps addressing these issues by: 1. focusing on the provision of reactive power services by the DSO to the TSO. A new version of the Interval Constrained Power Flow (ICPF) tool, which takes into account disjoint flexibility areas as a result of the combination of discrete control variables, will be used to evaluate the range of operation points at the primary substations (Figure 1). With this information, the TSO can then select an operation point that will cause minimum impact on the transmission network. Figure 1 – Example of flexibility area computed by the ICPF tool (red area obtained considering discrete variables as continuous ones; green area obtained by considering the combination of all possible values for the discrete values). 2. designing and implementing the information exchange needed to support other dimensions such as operational planning through nodal forecast at nodal level and exchange of maintenance plans in a defined observability area of both system operators (Figure 2). Figure 2 – Example of definition of observability area. Furthermore, one of the main outcomes of TDX-Assist concerns the proof of concept using field tests and demonstration with industry specification at both TSO and DSO levels. The Portuguese demonstrator, particularly, will focus on: 1. Coordination of operation planning activities between TSO and DSO. This will improve state estimation and provide valuable information for both system operators bearing in mind the results from the dayahead market; 2. Improve fault location close to the TSO-DSO interface. The aim is to achieve a maximum time delay of 5 minutes to send detailed information about the type of fault and its location; 3. Improve system real-time supervision and control through better coordination; 4. Application of the Interval Constrained and Sequential Optimal Power Flow tools, demonstrating the characterization and deployment of available flexibility services and congestion management from 25th International Conference on Electricity Distribution Madrid, 3-6 June 2019