It takes a lot of pieces to build an electrical substation. Some pieces, such as 294-ton transformers, are a little larger than others.
Brennon McKenzie, Basin Electric electrical engineer at the Mandan Transmission System Maintenance shop, and Dan Swigost, Basin Electric electrical consultant engineer, traveled to Nijmegen, Netherlands, in late March to help test a 600 megavolt ampere (MVA) transformer. The transformer, when drained of oil and ready to be shipped, weighs about 587,000 pounds.
This particular transformer is destined for Basin Electric’s Laramie River Station, located near Wheatland, WY. It’s the third unit of its kind Basin Electric has purchased in the last two years, McKenzie says. One lives in a 345-kilovolt switchyard at Leland Olds Station, located near Stanton, ND, and another is part of the Charlie Creek substation, located near Grassy Butte, ND. McKenzie has helped test all three transformers at the factory in Nijmegen.
McKenzie said the transformer must meet several testing standards put forth by the Institute of Electrical and Electronics Engineers. After testing, factory employees disassemble the transformers, drain 24,900 gallons of insulating mineral oil, seal the unit and fill it with nitrogen to prepare for transport.
“The units cross the Atlantic Ocean and usually arrive in the port of Houston, where they are transferred to a special rail car of which there are only a few in the United States,” McKenzie says.
The transformers travel by rail as far as possible until being transferred to a long, modular semi-trailer for transportation to its final location and put into service.
The recently-assembled transformer is currently aboard a large cargo ship that’s halfway across the Atlantic, and should be onsite at Laramie River in late May or early June.