Since more of the power lines are moving underground it has placed increased pressure on the cooperative’s fleet of rubber-tire utility tractors.
Jim Wimmer and Todd Johnson know that maintaining 8,000 mi. (12,874.8 km) of electric distribution lines is a challenge for any team, but spread that over 10,872 sq. mi. (28,160 sq km) in a state known for its 10,000 lakes and the challenge intensifies.
Wimmer and Johnson are area supervisors for Lake Country Power based in Grand Rapids, Minn. The rural electrical cooperative was formed back in 1997 and is currently the largest electrical cooperative in Minnesota, providing electricity and other energy-related services to more than 41,000 customers in the northern portion of the state.
This team is responsible for the installation and maintenance of the electrical system. This includes handling up to 900 new service connections each year, rebuilding existing distribution lines and addressing power outages.
“A lot of our work this past year has focused on rebuilding existing distribution lines and adding load,” said Wimmer. “We currently have about 6,300 miles of overhead lines and nearly 2,000 miles underground. In some service areas, like Grand Rapids, the ratio is closer to 60-to-40.”
However, the majority of the new installations and upgrades are moving underground.
“The movement to underground in our area is for cosmetic reasons,” said Johnson. “The cooperative members prefer to have an underground transformer sitting in their yard instead of lines coming in from a power pole.”
Lake Country Power is located in an area where small lakes are quite prevalent. Ground conditions can range from sand to clay within a matter of a few hundred feet, and bogs — a type of wetland — are commonplace. Add in steep sloping right-of-ways and you have a major test.
This all poses challenges to installing underground lines as the cooperative has a lot of old primary URD cable that is being extended. The cable insulation has deteriorated, so new cable is being installed.
Since more of the power lines are moving underground it has placed increased pressure on the cooperative’s fleet of rubber tire utility tractors. Primary and secondary lines can stretch for miles, and plowing into residential areas requires care and a small footprint. However, the rubber tire units have had difficulty pulling through the wet areas and lacked the traction needed for longer runs.
“Stability, traction and versatility are vital to navigating this part of the state,” said Johnson. “We also value the input of our crews and wanted a machine that would meet their needs and help enhance our productivity. In some cases our existing units weren’t able to complete projects, so we had to call in subcontractors. That takes extra time and money. We began testing various utility tractors to see which make and model would best fit our needs.”
Quads to the Rescue
Wimmer and Johnson listened to their crews and turned to Vermeer and its line of rubber quad-track utility tractors. The cooperative purchased a Vermeer RTX1250 in May 2008 and followed that with the purchase of two RTX750s in late November 2008 and April 2009. All three units are equipped with a vibratory plow and backhoe.
“We really like the stability, horsepower and traction offered by the RTX machines,” said Johnson. “The rubber quad-track system provides more contact with the ground and doesn’t cause as much damage to yards as compared to rubber tires. We’ve also discovered that the RTX machines have significantly more traction than rubber tire units, allowing us to plow up and down and alongside hills with more efficiency.”
The cooperative uses the RTX1250 for plowing longer haul projects and the RTX750s for installing secondary and working in more confined spaces. Both men recall various projects where the units have shined, but one near Leech Lake, located west of Grand Rapids, takes the cake.
Dealing with bogs and wet ground conditions is a major challenge in this area. The project near Leech Lake involved the installation of a new 400-ft. (121.9 m) service line on the east side of the lake. The line came off an overhead source pole that was located in a bog about 50 ft. (15.2 m) from the road and right-of-way.
“Ground conditions were very soft and in most cases we would have laid some padding or cribbing to support a rubber tire utility tractor,” said Wimmer. “But we were confident enough with the floatation of the RTX750 that we decided to forgo the cribbing and we weren’t disappointed. In fact the operator went in and out of the area three times and never broke through the bog.”
According to Wimmer, the RTX750 floatation was incredible and the operator used the backhoe to create a 3-ft.-deep (.9 m) trench out to the right-of-way. From there the unit plowed in the remaining 350 ft. (106.7 m) of cable to the residence.
Both units have shined when plowing cables along side hills.
“The RTX units have the ability to handle the variety of terrains we have around here with good stability and cause remarkably little turf damage to properties,” said Johnson.
Wimmer and Johnson like the flexibility of the RTX750 and RTX1250.
“We’re able to plow in many different terrains and soil types where before we were waiting on subcontractors to come in and handle a certain situation,” said Wimmer. “Now we can handle any job — that’s the biggest advantage for us.”