In a statement, Vestas confirmed the incident occurred on Friday afternoon. It said the wind speeds at the time were around 90 kilometres per hour and an investigation is under way into the causes of the incident.
A spokesman said: "Vestas takes safety extremely seriously. A thorough investigation will be conducted to establish the root cause of the incident. Until this has been conducted, Vestas cannot speculate on the cause of the incident."
In June 2012, Vestas said it was ending production of the the V52 and V60 850kW machines. In a statement the company said it was closing its factory in Hohhot, Inner Mongolia Autonomous Region and cut 300 jobs.
Vestas said it took the decision as it projected a low market for the kW range. It said it would honour all existing contracts and continue servicing the turbines.