A Nordex turbine failure at the 25MW Pant-y-Wal wind farm in south Wales earlier this year was caused by the machine running at overspeed for more than four hours, the manufacturer has said.
The N90/2500 machine collapsed in the early morning of 14 February, prompting an investigation into the cause of the incident.
Nordex said in a statement: “A Root Cause Analysis (RCA) investigation determined that a technical issue, starting within an uninterrupted power supply cabinet for one of the blades, triggered an unprecedented chain of events in quick succession.
“This disabled the main power supply and the backup power supply to each blade of the pitch system, therefore all three blades of the wind turbine were left without power resulting in a fixed state.
“The wind speed conditions on the day increased putting the wind turbine into an overspeed condition until it collapsed.”
Pant-y-Wal developer Pennant Walters has now removed the affected components from the site and placed them into storage.
The remaining nine wind turbines at the site in Bridgend County have been inspected to ensure their sound condition, Nordex added.
“A RAPEX analysis was carried out and the likelihood of human injury after a failure of this characterisation was classed as ‘low’, meaning wind turbines may continue to run.”
RAPEX is the European standard for product risk analysis, used by national authorities for evaluation and communication of product risk.