This paper present particle swarm optimization based study of multi area power network. Particle swarm optimization and Fuzzy system inferences have been employed to effectively obtain the optimized gains of PID controller. Any change in the load demand causes generator's shaft speed lower than the pre-set value and the system frequency deviates from the standard value results in malfunctioning of frequency relays. A three area load frequency model is constructed in Matlab/Simulink by implementing the PID controllers to control the frequency deviation on the three areas together and each area to illustrate the effect of frequency deviation on the integrated model. One of these areas is a nuclear power plant. Performance of the proposed controller is compared with fuzzy system based PID controller and conventional PID controller to indicate the excellence of the proposed algorithm for PID parameters regulation. Simulations performed show the effectiveness of the current approach over simple fuzzy inferences in terms of performance as well as execution efficiency.