Recent developments of distribution systems take advantages of new technical issues and networks equipments such as: DG (distributed generation), smart grids, smart metering, etc. The aim of the paper is to propose an approach for load/generation control in distribution grid based on the solution of an OPF (optimal power flow). The OPF dispatch local generation (DG), power injected by feeders and assess the load that needs to be curtailed in emergency conditions (isolated system, lack of, transport capacity onto the feeders, etc.). The proposed approach investigates about the possibility for distribution companies to reduce customer load up to 50% using signals coming from smart meters. The analysis also considers compensation costs for customers' supply interruption based on the actual Italian regulation.