Suzlon officials have determined that bolt failure caused a rotor assembly crash at the 149.1 MW Rugby Wind Power Project, located near Rugby, N.D., on March 14.
Speaking to NAW, Duncan Koerbel, president of Suzlon Global Services, says that the company's internal investigation had determined that bolts attaching the wind turbine's rotor and blades to a power shaft had failed. The shaft transfers the energy generated by the turning blades to an electric generator.
‘A misalignment occurred with the rotor flange between the hub and the shaft, causing abnormal stress to the bolts,’ Koerbel explains.
Working in conjunction with the wind farm's owner and operator, Iberdrola Renewables, Koerbel describes the incident as a ‘singular event,’ as this kind of defect had never been associated with the S88 turbine, the type of turbine that fell in Rugby. According to Suzlon, there are 1,100 S88 turbines operating in the U.S.
Mark Perryman, managing director of field services at Iberdrola Renewables, echoed Koerbel's statement. ‘Within our fleet, this is something that we've never seen before,’ Perryman says, referring to Iberdrola's 2,760 turbines, of which 341 are Suzlon S88 wind turbines.
Koerbel says the wind farm's 71 turbines were checked and resumed operation by the end of the week. He says a new set of blades and a hub have been ordered for the turbine. What is not yet clear, Suzlon says, is if the tower, which suffered a dent upon impact with the rotor, will need replacement.
Photo credit: Dan Smith, Dan Smith Photo, copyright 2011
