The aim of this paper is to present a new approach for the medium voltage (MV) distribution network load flow analysis, mainly based on power measurement at the low voltage (LV) level of MV/LV distribution substations. This allows to use measurement instruments, usually already installed in the secondary substations, thus achieving an equally reliable measurement system with a lower cost compared to measurements at the MV side. The new approach can be applied using a proper communication system to collect the nodal measurements and an iterative algorithm based on ladder iterative technique (LIT) to compute the load flow. The validity of this method is presented and discussed on the basis of the simulation results of Ustica island's distribution network.