Abstract: In order to ensure the safety of wind turbine design, the dynamic response characteristics of wind turbine drive chain under generator short-circuit condition were studied for a MW class double-fed wind turbine. Firstly, amulti-body dynamic simulation model of the drivetrain was established based on Simpack/ANSYS.Then, taking the electromagnetic torque generated by the generator short circuit as the excitation load, the torque transfer law of each shaft in the drivetrain was quantitatively analyzed, the influence of the moment of inertia of brake disc and coupling damping ratio on the dynamic response characteristics of the drivetrain was further studied.Finally,in order to verify the reliability of the above calculation results, the GH bladed was used to simulate the same unit model and the same working conditions, and the simulation consistency verification was carried out.The results indicate that the instantaneous torque peak attenuation at the high-speed output shaft and input shaft of the gearbox was the most significant under the generator short-circuit condition.In the two-phase short-circuit condition, the peak torque attenuation is 74.7% and 47.6% respectively compared with the previous stage, and in the three-phase short-circuit condition, the attenuation is 70.7% and 46.4%. Torque peak on the drivetrain is hysteretic compared with the electromagnetic torque. The moment of inertia of brake disc and coupling damping ratio have significant effects on the instantaneous torque of high-speed shaft. High rotational inertia and low damping ratio of coupling can lead to high instantaneous torque peak. The results have practical guiding significance for the analysis of generator shortcircuit fault and the safety evaluation and design of components at all stages of drivetrain.

Key words: mechanical transmission mechanism; drivetrain; generatorshort circuit;dynamic response characteristics; gearbox;coupling