Combined Planning of LVDC and MVDC Grids for Public Power Supply

Based on the large technological developments in the field of power electronic devices and DC technology, not only DC microgrids but also DC distribution grids for public power supply gain practical relevance. In this course, DC infrastructure promises to overcome some future challenges on MV and LV level. For the planning of MVDC and LVDC distribution grids, meta-heuristic optimization techniques have recently been applied in order to efficiently design either the LV or the MV level. However, an important aspect of the planning of novel DC grids is the combined optimization of LVDC and MVDC level in order to leverage economic potential. In this paper, a comprehensive planning framework for the combined LVDC and MVDC grid planning is presented. After providing a theoretical foundation for the DC grid planning task, the combined planning framework is presented. A hierarchical structure-dependent methodology has been developed deriving technically and economically optimized LVDC and MVDC distribution grids. The planning framework is applied within a case study on two supply areas: A rural and an urban region. The results show a significant reduction of cable trench lengths and costs when an incentive is set.