AbstractNowadays, ancillary services in electrical distribution networks (e. g. voltage support and reactive power control), usually provided by capacitor banks, start to be performed by distributed generation units (DGs). In this way, several papers have been studying the use of DGs as reactive power providers, and the power electronic/market regulation involved in this new scenario. However, the authors commonly consider a full implementation of Smart Grid philosophy, i. e., there are appropriate communications between DGs and distribution network operator (DNO)’s control centers, but it is not a close reality in many developing countries, due to high costs involved in their implementation. Therefore, this paper proposes a new method in order to use DGs as ancillary services providers in a short and medium-term (called in the literature Pre Smart Grid), in which there are not effective communications between DGs and control centers of DNOs. The proposed method uses a non-uniform DGs distribution, obtained from local atlas of wind, solar, hydraulic and biomass power. The methodology presented accurate results when compared with a PSO-based method, widely used to solve optimization problems, but needs a complete Smart Grid philosophy implementation to work.