Investigators have confirmed a fault in the pitch system caused a turbine to collapse at the 52.8MW Harvest 1 wind farm in Michigan.
A Vestas V82-1.65MW turbine at the Exelon Wind Generation project fell apart in February during a snowstorm.
“We determined the root cause to be failure of the seals on the cylinders in the pitch system,” said spokesperson Kristen Otterness.
The system had stopped the rotor due to high winds. However when the seals failed the loss of hydraulic pressure left the blades to spin out of control, explained Otterness. The excessive load caused the tower to collapse.
The turbine is designed to operate at a maximum rotor speed of about 14 rpm. “Our data shows that the rotor was spinning at about 18 rpm at the time of the event,” said Otterness.
Exelon has inspected the other V82 turbines and replaced cylinders when wear was detected. The company has put in place early detection, notification and diagnostic systems to improve monitoring.
“We are fully committed to making sure an event like the one at the Harvest 1 project doesn’t happen anywhere else across our fleet,” said Otterness. Three Exelon wind farms in Oregon employ the same type of turbine
The company has yet to decide whether to replace the turbine at Harvest 1, where the remaining turbines continue to operate normally.
Image: the nearby Harvest II project which features Vestas V100-1.8MW turbines (Exelon)
