Due to the increasing development of Distributed Generation (DG) based on renewable energy sources (RESs), currently voltage control represents an important issue in distribution power systems. In this paper, we propose a comparison between two voltage control methods that allow obtaining the maximum available power production from wind turbines and photovoltaic systems. Both methods suppose a wind and photovoltaic plants belonging to an Independent Power Producer (IPP) able to control each RES units. The first method is based on a coordinated local control approach that takes advantage of a mixed Distribution Network (DN) sensitivity analysis; the second one is based on a cooperation of data transfer between Distribution Systems Operator (DSO) and IPP in order to maintain voltage levels within mandatory limits. The comparison is conducted by means of a time series simulation analysis on a real MV Italian distribution system. © 2014 IEEE.