Planning Aspects of MVDC Distribution System Interconnections including Analysis of a new Use Case

The continuous increase of renewable energy generation is a challenging task for todays distribution system operators. The renewable generation within one distribution system can exceed local loads by far and causes an increasing demand for cost-intensive interventions in the power plant dispatch or RE curtailments. To reduce these emergency actions, an approach of interconnecting distribution systems via MVDC-links to enable a horizontal controllable power exchange appears in current researches. However, one asset shared by two system operators is a challenge when it comes to power system planning. Also, distribution system operators are usually unexperienced with DC technology within distribution systems. This paper presents an approach to design an aligned planning process for the DSOs by using a toolbox as support. Also, the analysis of potential use cases is an important part of a planning procedure. Therefore, the use case of reducing redispatch by creating a parallel power flow path through the distribution grids has been examined, by determining the potential distribution system power transfer capability using sensitivity analysis. Also, the impact of transmission system expansion on the distribution system power transfer capability has been examined.