Keywords: Wind turbines

ha farms to the grid may cause problems in terms of power quality due to the variability of the energy customer equipment [4]. Power quality decrement is generally caused by many factors such as impulsive and transients, over volt-age or under voltage variations, voltage imbalance, waveform dis-tortion, such as dc offset, harmonics, notching and noise, voltage fluctuation and frequency variations. In recent years, concern over power quality has increased significantly due to economic reasons and problems that can affect the manufacturing industries and the other customers [5]. the wind turbine installation to a specific grid [8,9]. Similar to that case, specifically in Turkey, a rule such as that the total wind power should not exceed 5 % of the short circuit power of the grid is mostly applied [10]. Although these kinds of rules are usable for preventing the power quality problems caused by wind power in a grid, the wind power exploitation, particularly in weak grids is greatly decreased due to these rules. In order to increase the exploitation, it is quiet convenient to utilize the power quality standards for wind turbines, issued by the International Electro-technical Commission (IEC). With utilizing the standard IEC 61400-21, which defines the power quality characteristic of gri