This document aims to provide basic knowledge on wind turbine generation system modelling, including mechanical and electrical systems. The documents explain the principles of aerodynamics and mechanics taken place in wind turbines, how operation and control of wind generation systems commonly used using pitch angle controller and angular speed controller work, and how to simulate turbine dynamics response. A grid model based on a synchronous generator is presented and different variations from the basic model of the wind turbine are used to provide primary frequency control to see the grid response. A 5 MW wind turbine is simulated using Matlab Simulink in order to see how wind turbines provide primary frequency control in the UK grid and if it will be able to provide it in a future with less non-renewable energies.