National Wind Watch: Wind Energy News » Liberty Utilities still trying to repair transformers for Neosho Ridge Wind

GALESBURG – The wind turbines remain idle in Neosho Ridge Wind more than two months after two transformers malfunctioned.

The industrial wind complex has 139 turbines located mostly in and around Galesburg and Thayer.

“We continue our efforts to restore operations at the Neosho Ridge Wind farm. The two transformers that failed are en route to the manufacturer for repairs,” said Kelli Price, Liberty Utilities senior manager of communications and marketing. “They weigh approximately 200,000 pounds each and are being transported by rail. We do not have a specific time frame for repairs.”

To protect the structures during the outage, crews are installing blade socks, Price said.

People in the area have been watching the socks being installed, which has increased questions of how long the turbines will stand inactive.

“Our focus remains on returning to normal operations as quickly as possible,” she said. “Our operations and engineering teams are exploring options to bring the wind farm back online while the transformer repairs are underway, but that work is ongoing, and we do not have specifics to share at this time.”

Wind turbine transformers do fail, according to various professionals and academic papers published the last 12 years.

The transformers act as a link between the turbines and the electrical distribution grid, stepping up lower output voltage from generators to a higher distribution level. In terms of equipment, wind transformers have been deemed sensitive due to the turbines’ variable speed and variable output, which are said to be the greatest cause of transformer failure.

Wind turbines operate intermittently. This imposes different demands on transformers, so standard distribution transformers must be modified for wind power distribution to avoid electrical, mechanical and other problems.

In a rush to install wind turbines, developers may trade low initial costs of buying off-the-shelf standard distribution transformers for higher total costs of ownership eventually shouldered by wind farm owners and operators, according to Tom Steeber, vice president of Pacific Crest Transformers of Medford, Oregon, in an article in Windpower Engineering Development. Steeber noted a variety of potential problems in wind production transformers, including loading factors, hazards from harmonics causing overheating and sizing and voltage variations.

Outside of those causes, a not so common cause for transformer malfunction is vandalism. There have been multiple cases in the U.S. of transformers, distribution lines and/or turbines being shot or otherwise vandalized.

“The investigation regarding what caused the failures is still underway. The root cause analysis is not complete,” Price said. “We do have insurance coverage and warranties on the transformers.

“We appreciate everyone’s patience as we conduct this thorough and complex work to understand what occurred, make necessary repairs and find solutions to re-energize the wind farm as soon as possible.”