Large-scale renewable energy sources (RESs) is becoming reality all over the world due to demand of clean and environmentally friendly energy. Many developed countries have integrated RESs into the existing system. Among numerous type of RESs, wind power system is becoming more popular due to technological advances. However, RESs could also bring negative impact on system stability such as frequency stability due to uncertainty power output of RESs. Hence, it is necessary to handle that problem by optimally extracting wind energy. Hence this paper focusing on extracting energy from wind speed using blade pitch angle controller (PI controller) to enhance the frequency stability of wind power system. To get better performance, improved differential evolution algorithm (IDEA) is used to optimize the PI controller of blade pitch angle. In order to analyze the impact of proposed method wind turbine load frequency control (LFC) model is used as a test system. Time domain simulation is used to examine the enhancement of frequency stability using the proposed method. From the simulation result, it is found that the proposed method could enhance the frequency performance on wind power system indicated by the lowest overshoot and the fastest settling time than any other scenarios.