Solomon engineer presents at wind energy industry conference

April 13, 2017

As the country strives to increase its renewable energy output and reduce its overall carbon footprint, wind power has become more important, especially in recent years.

In 2015, wind power represented almost five percent of the electricity generated in the U.S., with an installed capacity of more than 70 gigawatts, which is enough to power more than 18 million homes. The same year, the Department of Energy’s vision for wind called for 10 percent generation by wind by 2020, 30 percent by 2030, and 35 percent by 2050.

In addition to meeting the challenge of installing enough new turbines to meet the department’s ambitious goals, the wind energy industry is facing the issue of aging equipment at wind farms. There are approximately 25,000 padmounted transformers in service at wind farms across the country. Of those, 20 to 30 percent are exhibiting combustible, gassing issues. We are using our expertise to provide solutions for the aging equipment.

Sharing our expertise

Ken Puetz, Solomon Corp’s Director of Engineering, provided his expertise in transformer redesign and testing at the 2017 American Wind Energy Association’s Operations, Maintenance and Safety Conference held recently in San Diego, California. The event is the premier conference for operators of wind farms in the U.S. and has been growing in popularity and attendance every year since the first event over ten years ago.

During the panel discussion, Ken provided several case studies that detailed defects found during our inspection and testing of wind farm padmount transformers that were developing combustible gasses or had actually failed while in service. Some other topics he covered included:

  • Improved design specifications to make wind farm transformers more durable
  • Increased BIL ratings of coils and internal lead structures to reduce electrical stresses
  • Improved core grounding procedures, which reduces the development of capacitance voltage in the core laminations near the HV windings and can result in partial discharge and arcing between individual core laminations
  • Installation of electrostatic shields to reduce harmonics and impulses from traveling through the transformer

Addressing failure rate in wind farm transformers

The wind farm industry does not have a specific standard for the type of transformer required. This has resulted in the transformer manufacturers building these transformers with same specifications used for standard utility transformers to reduce costs.

“The standard utility transformer has had a poor track record in performance in wind farm applications,” Ken said. “The industry is working to develop a wind farm transformer specification, which will help eliminate most of the problem we are currently seeing.”

There are many causes for failure in wind farm pad mounted transformers. “The most common causes of failure or need for repair is related to internal electrical stresses which results in the development of combustible gasses,” Ken said. These electrical stresses are a result of improper core grounding, lead structure insulation, and component failure.

One of the case studies Ken presented was a wind farm padmount transformer failure caused by the HV tap changer. The HV tap changer develops a high resistance connection between the stationary and moving contacts, resulting in an internal hot spot on the HV tap changer connections. The connection point continued to deteriorate until it failed resulting in a direct short across the HV windings.

Leading the way

Solomon Corporation is taking the lead in the diagnostics, repair and replacement of aging wind farm transformers. To help wind energy producers, Solomon Corporation has developed its own wind farm transformer specification to solve the issues with failure and development of combustible gasses. We can bring in a wind farm transformer that has failed or developing combustible gasses and repair it to our specifications or we can provide a replacement unit from our inventory as well.

For more information or to request a quote, visit us at www.solomoncorp.com or call 800-234-2867.