Performance and Operation Management - Wind Energy Systems for Electric Power Generation - page 139

Short-circuit and fault ride-through properties required by transmission system
operators as discussed in 7.5.1, however, can be met only if the WES is capable of
continuing service without disconnection under voltage drop, as long as the voltage
is above an established curve versus time, e.g. as shown in Fig. 7.10. Also the wind
turbine system is expected to contribute a limited portion to the short current in the
point of connection. These requirements set up by utilities have been a technical
challenge to the wind system industry.