Abstract :
Comparing performances and costs is a centre of interest for all regulators and distributions companies. This paper focuses on medium voltage grids, and tries to explain the differences in length that can be observed in European countries. Electric supply disturbances and costs are supposed to be related to those lengths. The analysis is based on a geometrical model, where parameters such as substation and load densities, or number of feeder, can vary. Main conclusion is that MV grid length is linked to dwelling surface. Natural characteristic such as load dispersion, and distribution companies structuring action such as introducing new substation or new feeder have second order impacts on grid length, with the same order of magnitude.