Impact of Grid Topology and Tap Position Changes on the Flexibility Provision from Distribution Grids

Abstract

With increasing penetration of DER in distribution grids, the use of flexibility provided by these new resources for ancillary services is gaining relevance. Changes in the topology of a distribution grid can influence the provision of flexibility, since grid constraints are modified. Therefore, the impact of operating radial and meshed grids is assessed in this paper. A method to aggregate the flexibility provision within a distribution grid is used to quantify this impact. A case study was performed using the adapted CIGRE MV test-bench grid. The feasible operation region of a grid was calculated under several discrete switching combinations, combined with a transformer with tap changer. Results showed that grids with meshed topologies have an increased ability to provide flexibility, due to the homogenization of power flows among the branches. Critical scenarios were observed in radial structures with large branch distances.