This article presents a hybrid optimization technique particle swarm optimization-gravitational search algorithm for optimal over-current relay coordination. The main contribution of this article is to find the optimized relay settings during variation in environmental factors that affect distributed generation performance. The detailed model of wind and photovoltaic source, modeled in a PSCAD/EMTDC platform is penetrated in a 13-bus distribution system. The optimal relay settings are found for different cases, including change in wind speed, change in penetration level, change in cell temperature, and insolation level of photovoltaic. A comparison of particle swarm optimization-gravitational search algorithm with particle swarm optimization and gravitational search algorithm technique is also done, and it is shown that the particle swarm optimization-gravitational search algorithm is a superior method that can be applied in relay coordination tasks.