An integrating distributed generation to power systems causes several technical issues, especially system stability like voltage at point of common coupling (PCC) and system. Therefore, to fully address the issue, current exiting power systems should be upgraded to the advanced power grid. To make the power grid become 'advanced', particularly in terms of stability and flexibility, one must need to make a controller which capable to control the above issue after integration of hybrid distribution generation system into the utility grid. All the issues have been attempted to address in this paper. Dynamic model for the main system components, namely, wind energy conversion system (WECS), PV energy conversion system (PVECS) and control for PVECS and the power electronics devices are addressed in this paper. The overall control strategy for grid connected hybrid wind/PV distributed generation system has also been presented. Different energy sources in the system are integrated through a DC bus into the utility grid. Based on the dynamic component models, a simulation model for the hybrid distributed generation system connected with utility grid has been developed using MATLAB/Simulink. Hybrid system comprises of Wind Turbine (WT) and solar Photovoltaic (SPV). For control the voltage and frequency at PCC Firefly based controller is used. Performance of several controllers such as Proportional Integral (PI), and Proportional Integral Derivatives (PID) are evaluated to control the frequency of the system. The controller gains are simultaneously optimized by powerful meta-heuristic firefly algorithm. Comparison of the dynamic responses reveals better performance of the PID controller. Here, it has been observed that the values of gain designed by firefly algorithm are robust which is verified and validated by case studies. Investigations reveal that the FA is successfully applied for simulation studies and it has been carried out to verify the controller and system performance under different scenarios which reveals that overall control strategy are robust and perform well. (C) 2017 Elsevier Ltd. All rights reserved.