SUMMARY
As more and more wind farms are installed in power systems around the world, frequency fluctuations due to output power variations have become a serious problem. Various countermeasures for the problem, such as battery systems, have been investigated. It is very important to evaluate the magnitude of the frequency fluctuations in order to design compensating systems. This paper presents a new and simple method to evaluate the expected value of the frequency deviation due to variations in wind farm output, which is based on the intensity of turbulence and annual probability distribution for the wind speed.