Wind Turbine Failure, Ohio

Assignment

Envista Forensics was assigned to investigate the nature, extent and cause of damage to a wind turbine that disconnected from the tower it was mounted to and fell to the ground.

Activities

Envista electrical and mechanical engineering teams conducted a site inspection at the loss site. This investigation consisted of an inspection of the damaged wind turbine, as well as two identical functional turbines. Envista engineers also inspected utility buildings and related equipment, as well as reviewed maintenance and service history for all pieces of equipment. Past maintenance history included the now-failed turbine being returned to the manufacturer for modifications to the blades prior to the catastrophic failure.

Outcome

Following our inspections and review, Envista was able to determine that the turbine failed due to excessive vibrations in the rotor which occurred after being sent to the manufacturer for blade modifications. As a result of these vibrations, the fiberglass blades failed prematurely and broke while rotating. This caused a severe imbalance which sheared mounting bolts, causing the nacelle to fall to the ground. Envista engineers' recommendation, due to the severe damage throughout the nacelle due to ground impact, was to replace the unit in order to restore to a pre-loss condition.