Determination of Interdependent Feasible Operation Regions at Multiple TSO-DSO Interconnections

As the share of decentral energy resources (DER) in the energy supply increases, the distribution system operator (DSO) gains flexibility potential in his system. In contrast, the transmission system operator (TSO) loses flexibilities. Closer cooperation between DSO and TSO is therefore essential. The Feasible Operation Region (FOR) offers an approach for providing flexibility at the vertical interface and can be used for such TSO-DSO cooperation. So far, the FOR-concept can only be applied to systems with one vertical interconnection. Therefore, this paper presents two novel methods that allow the FOR-concept to be applied to multiple vertical interconnections. The first method is called the static method, which is a straightforward and time consuming approach. In order to reduce the computation time, an iterative method between the two system operators is developed. Based on a system with two vertical interconnections, the iterative method is plausibilised within the congestion management of the TSO and compared with the static method in terms of computing time. The methods developed in this paper provide a full concept for handling multiple interconnections, while retaining the full potential of the FOR-concept.