Overview of power quality aspects in wind generation

The interest for renewable energy sources has increased significantly due to environmental issues and fossil fuels elevated cost. Due to this, wind energy has gained a lot of investments from all over the world. However, due to the wind speed´s uncertain behavior it is difficult to obtain good quality power, since wind speed fluctuations reflect on the voltage and active power output of the electric machine connected to the wind turbine. This brings great challenges to power systems engineering, since new control schemes must be adopted in order to deal with those fluctuations and new techniques must be developed in order to improve wind power plant´s performance. Not only that, but the use of induction generators presents safety issues due to possible self-excitation. This article aims to demonstrate state-of-the-art technologies used to improve wind power quality and reliability. A energy storage technique focused on improving wind power reliability and availabity but also smoothening wind power variations is presented. The use of a static compensator (STATCOM) in order to deal with harmonic current injection, reactive power compensation and voltage variation is discussed. The usage of a wind energy conversion and storage system is also presented, this technique aims to improve wind power quality and wind plant´s fault tolerance. The lack of reactive power compensation issue is also treated, by investigating the use of a Dynamic Voltage Restorer in a distribution grid connected to a wind turbine driving a induction generator. A brief insight of wind power future and possible integration with Plug in Hybrid Electrical Vehicles is also provided. At last a brief overview of the topics covered is presented and conclusions are made.