As a main electric power source for remote area, standalone diesel generators have many problems such as operation at a load factor below 50%, cost of fuel including transportation and Co2 emissions. So the hybrid renewable wind-diesel system is a must for solving that problem. The output power of wind turbine is proportional to the cube of wind speed, which causes the fluctuations of the generated output power that may lead to frequency deviation for the hybrid micro grid system. Consequently, frequency is one of the conditions of quality conditions of any micro grid. So keeping frequency within the allowable standard limits is main objective. The micro grid system is consists of 150 KW wind turbine generator, 200 KW diesel generator to feed a load. MOPSO algorithm optimizes the gains of the blade pitch PID controller of the wind turbine generator. The proposed system is compared with GA-PID optimized and classical PI controllers. Simulation has been carried out with a step disturbance in wind input and load power with sensitivity analysis based on parameter variation. Results prove the robustness of MOPSO based scheme that damps the oscillations in the system frequency deviation response.