An optimal way of real and reactive power management in radial distribution systems with distributed generations (DG) to improve the voltage profile is presented in this paper. Distributed generations effectively reduce the real power loss in radial distribution system compared to other methods of loss reduction and simultaneously improve the reliability of the system. In this paper, a solution methodology based on the voltage stability index has been proposed for optimal siting of distributed generations. The optimal sizing of the sources has also been carried out using genetic algorithm for better voltage regulation, voltage stability index and reduced network power loss in the radial distribution system. An emphasis is laid in this paper on the application of wind turbine generator system (WTGS) because of the distinct behaviour of the induction generators present in them. A detailed performance analysis is carried out on Indian 25 bus system, 33 and 69 bus systems to demonstrate the effectiveness of the proposed methodology.