Several potential benefits of integrating renewable energy based distributed generation (DG) units to conventional distribution systems have been seen. The power input from renewable DG units placed close to the load centres provide an opportunity for system voltage support, reduction in energy losses and emissions, and reliability improvement. Therefore, the allocation of DG units and their optimal sizing is an important concern. This paper presents a simple approach for real power loss reduction, voltage profile improvement, substation capacity release and is based on voltage sensitivity index analysis. Load flow analysis is done using the forward-backward sweep method. Study carried out on an IEEE-33 bus test system validates the suitability of this proposed method