Firstly, the general framework conditions of the elements of the energy transition are analysed with a focus on the conditions relevant to grid planning. Furthermore, their future development in terms of development scenarios is investigated. At this point, the expected development of each element of the energy transition is determined. Afterwards, the methodology of the strategic grid planning is developed. This methodology converts the analysed framework conditions and the development scenarios into load and feed-in values that can be modelled in the grids. Based on this modelling, the future supply and generation tasks of the grids are mapped. Consequently, the grid limits are identified. In the case of a violation, possible conventional and innovative planning measures are proposed. Subsequently, a clustering algorithm is applied to a dataset of medium-voltage grids to determine representative urban medium-voltage grids. The developed methodology of the strategic grid planning is applied to these representative grids, thus resulting in several planning alternatives. These planning alternatives are assessed technically as well as economically. Finally, a set of generally valid planning guidelines specifically tailored for urban medium-voltage grids are presented. These planning guidelines are methodologically deduced based on the assessed results of the strategic grid planning methodology for the chosen representative urban medium-voltage grids