Impact of Wind Turbines on Voltage Stability of Power Systems: Assessment and Improvement

Increasing penetration level of wind turbines in power systems has created new challenges for power engineers. One of such important challenges is voltage stability of power system. According to the studies, when a synchronous generator is replaced by a wind turbine, voltage stability deteriorates. In this paper, voltage stability of power systems in the presence of different types of wind turbines is studied. First, considering the different stability indicators, impact of different types of wind turbines on voltage stability is compared with each other. Then, impact of different control modes of variable speed wind turbines on voltage stability is evaluated. Also, due to the high impact of output reactive power of variable speed wind turbines on the voltage stability indicators, both during and after the fault, a method based on mathematical calculations has been proposed to obtain the optimal reference value of reactive power. Effectiveness of the proposed method in voltage stability improvement has been shown via simulations performed by MATLAB/Simulink software.