This paper presents a new optimization algorithm to design an optimal proportional, integral, derivative (PID) controller in hydro-turbine generator governor for damping output frequency oscillations. In this research, we utilize a stochastic and optimal based PID controller to control frequency-response of the hydro turbine. The proposed algorithm is employed to design an optimal PID controller by adjusting the PID parameters. Here, the parameters of the PID controller are optimized by IWO Algorithm. For analyzing the proposed technique, the final results of IWO algorithm is compared with ABC algorithm. Simulation results showed that the proposed method has better performance in different load condition of power system. Manuscript profile