Power quality investigation of grid connected wind turbines

With the continued expansion of the scale of wind power generation, the power quality problems due to grid connected wind farms are concerned widely. The voltage fluctuation and flicker and harmonics are main aspects of power quality problems. The fluctuation of wind farm output and grid voltage due to the random fluctuation of wind speed and inherent characteristics of wind turbines may cause flicker severity. It is significant to investigate the impact of power quality on load and operation of power system. In this paper, the wind turbine instantaneously generated power and voltage at the point of common connection (PCC) with grid are simulated by considering all the aero dynamical and mechanical effects, which could affect them. The inherent effect of the wind speed on the entire blade swept area is simulated in the model of the wind speed. The generated power is obtained by the simulation of the wind speed time series into a wind turbine model. The flickermeter model which expresses voltage fluctuations is simulated according to the IEC standard 61000-4-15. The wind speed, wind turbine and flickermeter models are simulated in Matlab/Simulink software. Both of grid and site parameters, which affect voltage fluctuation, are investigated. These parameters have a wide influence on voltage fluctuation and flicker emission levels.