Modeling of Wind Turbines Equipped with Induction Machines for Voltage Profile Studies Using PSCAD

As a result of increasing environmental concern, more and more electricity is generated from wind turbines. Therefore, adequate models to study the impact of wind turbines on electrical power system behavior are needed. One of the most important considerations is the effect of wind turbines on the voltage profile, i.e. the induced slow voltage variations, which are the subject of this paper. The wind turbines can be operated in two modes: constant-speed and variable-speed. Each one of these cases has different impact on steady state voltage of distribution grids. For evaluation of these impacts, SCIG generator has been simulated that works in constant-speed operation and DFIG generator that is used in a variable-speed turbine. Variable-speed wind turbines can be controlled in two ways. They can produce power with constant power factor or they control magnitude of voltage of PCC. PSCAD/EMTDC simulation program is used to investigate the impact of these turbines on a distribution grid. The outcomes of the simulation demonstrate the effectiveness of the proposed simulation and control schemes. Also, it is shown that voltage control scheme has better results and improves the voltage profile considerably.