Utilization of distributed energy resources (DER’s) like photo-voltaic generators, is one of the possible solution for present scenario of energy crisis. Most of the study suggest the implementation of PV power stations at distribution level. In this paper detailed theoretical analyses of the impact of large scale PV on transmission level is analysed. The preliminary section of this paper provides literature review with specifications of IEEE-14 bus network. Two methodology ie, constant load method and maximum loading method is implemented here. A test study is done in IEEE 14 bus to find out the optimal location of solar photo-voltaic generator (SPVG)and to find the maximum safe instantaneous penetration with both method using genetic algorithm (GA). Maximum penetration is achieved by adjusting grid parameters subjected to various power system stability and security constraints. Finally it can be concluded that GA based optimal control of large scale PV penetration allows us to utilize SPV power efficiently.