In recent years several studies regarding optimal operation of distribution networks in presence of Distributed Generation (DG) were proposed. This paper describes an algorithm developed by RSE (DISCOVER) to increase the hosting capacity of the network by means of Voltage control of Medium Voltage feeders in presence of storage units. The system, which coordinates controllable resources present in the MV network connected to the HV/MV transformer, is conceived to compute the set-points of the distributed energy resources (generators, storage) controllers and On Load Tap Changer (OLTC) in real-time according to specified economic and technical objectives. It is assumed that storage units are operated directly by the Distribution Company in order to increase network control capabilities. Because storage units on the whole should maintain a desired energy level, this involves to resolve simultaneously more temporal intervals (for instance 96 quarter of hours for a day) with integral constraints in the optimization problem. The algorithm is based on an AC Optimal Power Flow (OPF) where losses and integral constraints are taken into account. Starting from forecasted load and generation, and considering technical constraints and dispatching costs for active and for reactive power, the algorithm generates for each time period a set of commands for controllable resources that guarantees achievement of technical goals minimizing the overall dispatching cost. The paper describes the general problem, how different resources are managed by the algorithm with respect to their technical and economic features, and some further details regarding storage units (main technical characteristics, time horizon for integral constraint, indicative operation costs and their effect on Voltage Control). Preliminary results achieved from simulation activity on the test network (based on a real MV grid) are given.