Burt Switching Station gets new transformer

July 29, 2020

Flip the switch and the light comes on.

The thought seems easy enough, but much more goes into supplying electricity to a home and/or business. As hundreds of generation stations work across the Southwest Power Pool footprint creating electricity, thousands of miles of transmission and distribution lines deliver that power to homes.

Before power arrives to a distribution system’s power lines, it goes through transformers on Corn Belt Power’s system. In June, Corn Belt Power upgraded its transformer inside the Burt Switching Station (Burt).

Replacing a transformer on a transmission system is no easy task. Delta Star began manufacturing the new 84 megavolt-ampere Burt transformer in May of 2019. The new transformer weighs more than 120,000 pounds empty. When filled with more than 9,000 gallons of oil, the transformer weighs 213,305 pounds.

“Ordering, manufacturing and shipping a transformer is quite a process,” said Mike Finnegan, system electrical superintendent, Corn Belt Power. “Typically it takes up to eight weeks to finalize construction plans. Once we get final approval, it can take anywhere from 20 weeks to one year to manufacture the transformer.”

Corn Belt Power studies its system and loads to determine transformer need.

“We use a program called Power Systems Simulator for Engineers,” said Tyler Baxter, engineer III, Corn Belt Power. “To begin with, we run five and 10 year summer peak models. We then run models on potential line outages, we call them ‘contingencies.’ We do this to ensure that no combination of line outages on our system could possibly overload a new transformer. We do several calculations before finally determining size.”

The old transformer at Burt wasn’t replaced due to age or damage, rather it was replaced because of load growth on the Corn Belt Power system.  

“We noticed the transformer started to show signs that it could overload,” said Baxter. “Modeling suggested we needed to upgrade the existing transformer.”

Once Corn Belt Power determines a location needs a new transformer, a contract bidding process takes place. After the contract is awarded, it’s a waiting game for the new transformer to be manufactured. While manufacturing is the most important aspect of the process, the transformer still needs to make its way to Corn Belt Power’s service territory.

“It’s no easy task shipping a piece of equipment that’s so heavy,” said Finnegan. “It took 20 days to ship from Canada to our Burt location, outside of Algona.”

The transformer left Canada on May 8 and encountered the following obstacles. Shortly after leaving Canada, the truck hauling the transformer was stopped by the New York Department of Transportation. The NYDOT stopped travel until May 19, when the truck could have a police escort. The transformer was stopped in Indiana on May 22. Once a police escort became available, travel resumed on May 26.

The transformer arrived in Algona at 12 p.m. on May 27 and crews placed the new transformer on May 28.

Finnegan says the old transformer will be used as a backup.

“We poured a spare concrete pad and moved the old transformer onto it,” he said. “We will keep the old transformer as a spare in case we have a failure somewhere in the system. With lead times for a new transformer varying between six months to 14 months it could place our system in a compromising position without a backup. The backup will help ensure reliability of our system.”