This paper proposes an automatic voltage control method for distribution networks using distributed generators connected to the grid in order to maintain voltage levels and to provide reactive power. This method consists in exchanging information withn a two-layer hierarchical control structure. The first one is the local control, responsible for monitoring each generator operating conditions.
The second one is the central control, responsible for providing the appropriate setpoints to each local control with an algorithm based on the sensitivity theory. This method is based on a sensitivity theory that chooses the generator which will cause the major impact on the network voltage profile when changing its reactive power injection. In order to test the proposed method, the authors implemented the IEEE 13-node test feeder in the Real Time Digital Simulator at Escola Politecnica da Universidade de Sao Paulo – Brazil.