A typical fixed speed wind farm connected to a simple grid is modelled. Using this model, a three-phase fault is applied close to the wind farm, and cleared by disconnecting the affected line. The effect of several electric, mechanical and operational parameters on the critical fault-clearing time of this base case is evaluated and discussed. The studied parameters are the short-circuit power at the connection bus, the reactive power compensation, the distance to the fault, the rotor inertia, the hub-generator resonant frequency, the wind speed and the power output. For each parameter, the relationship between its value and the critical fault-clearing time is shown graphically. The results help to understand the transient stability phenomena in fixed speed wind farms, and could help to design fixed speed wind farms attending to transient stability requirements. (C) 2003 Elsevier Science Ltd. All rights reserved.