Calculating multi-period cost curves of aggregated reactive power flexibility in active distribution grids for TSO-DSO coordination

Authors

Capitanescu F.

Reference

Sustainable Energy Grids and Networks, vol. 43, art. no. 101922, 2025

Description

The reactive power flexibility of distributed energy resources connected to active distribution systems can support transmission grid voltages if the operators of distribution and transmission systems coordinate their operations. Computing cost curves of reactive power aggregated flexibility of an active distribution system at the interface with the transmission grid is moderately challenging for a single time. However, the time coupling of on-load tap changing transformer operation challenges the calculation of cost curves in a multi-period timeframe. This paper proposes for the first time a methodology to calculate piece-wise linear cost curves of reactive power flexibility of an active distribution system. The core of the approach relies on combining tailored multi-period AC optimal reactive power flow calculations with different objectives and sets of constraints, formulated as mixed-integer nonlinear programming problems. The feasibility of the methodology is demonstrated using an active distribution system of 34 nodes for 24 time periods. The results show that distributed energy resources have the potential to jointly deliver significant amounts of reactive power flexibility, both upward and downward, at the operators’ interface. The paper unveils new insights into this complex problem.

Link

doi:10.1016/j.segan.2025.101922