Small-disturbance voltage stability of distribution systems with wind turbine implemented with WRIG

The small-disturbance voltage stability of a grid-connected wound-rotor induction-generator (WRIG) wind-turbine system is analyzed under different operating conditions. This theoretical study shows the effect of the wound-rotor induction generator and its parameters on load-bus voltage collapse phenomena. Results show that the rotor resistance of the induction generators may decrease the system voltage stability margin and that the transmission line length has an important effect on the maximum loading point and critical point of loading.