An analysis has been completed and an explanation was give to the Huron County Planning Commission regarding a wind turbine that collapsed in Oliver Township back in February. Exelon Communications Manager Kristen Otterness says that the root cause was a failure of three seals on the cylinders due to wear on them, which set in motion a sequence of events that caused the collapse of the wind turbine.
After a hydraulic pump was shut off automatically due to high winds during a winter storm that day, an 'over speed event' occurred as the revolutions per minute of the blades far exceeded what the structure could handle. According to Vestas Canadian Wind Technology Operations Manager Mark Van Diepenbeek, if even one of the cylinders had not been worn, the failure would not have occurred.
The event is extremely rare and it is the first time the company has dealt with a collapsed turbine in their entire U.S. fleet, which includes 47 wind farms. Exelon has increased monitoring of all their turbines locally and nationally. They are inspecting the seals of all cylinders and performing repairs in the Harvest Wind #1 wind park which has been in service for over seven years. So far, they have found some wear on the cylinders seals in some other turbines, but not any that have wear on all three seals. The sequence that led to the collapse occurred over an eight hour period.
Estimated winds were just over 40mph sustained and the turbine was not operating at the time it fell near an area of Maxwell Road between Berne and Richardson Roads. The collapse did not cause any injuries.