One of the questions of the research on smart grids is how to involve the growing number of distributed generators (DG's) into the voltage stability control, and more in general in the power quality management, of a distribution line. The challenge consists in minimizing the involvement of DG's connected to a renewable energy source and the required reactive power. This work presents an approach to control the voltage over a radial feeder, featuring a multi-agent system. Using distributed intelligence like a multi-agent system to control the DG's allows avoiding single point of failure in the grid, one of the most important features of an electrical network. The agents organize the power dispatch and increase its performance by taking into account the resistive part of the line - which is in most cases not negligible in distribution feeder - and by offering a way to dynamically update the parameters needed for the dispatch.