Optimal Power Flow for Multi-Use Case Operation of Integrated DC Sections in Distribution Systems

Abstract:
In the context of the ongoing energy transition the introduction of DC technology can support the necessary enhancement of transmission and distribution capacities and flexibility in the power system. Especially for distribution systems there is still a lack of methods for planning and operation of hybrid AC/DC systems. Therefore, this paper presents a refined approach for optimal power flow based multi-use case operation of integrated DC sections in normal operation of distribution systems. The optimal power flow formulation incorporates three single use cases, which are the relief of highly loaded grid sections, the reduction of grid losses and the improvement of voltage quality. The possible benefit of the presented approach is studied in a numerical case study on a representative medium voltage distribution system. The evaluation of the single use cases as well as their mutual interrelations and interferences in multi-use case operation highlights the chances and limitations related to integrated DC sections in distribution systems.