By Starrla Cray
DELANO, MN Pretty soon, there won’t be any sign of unsightly overhead power lines in Delano.
Delano Municipal Utilities (DMU) has been working to put in underground cables in an effort to beautify the city, increase system reliability, and prepare for a possible industrial park north of town.
“We have about 90 percent buried so far,” DMU general manager Hal Becker said.
The plan is to have all overhead lines in Delano buried within two to four years.
“It basically depends on how much work comes in at the same time,” Becker said.
Most of the overhead lines in Delano are more than 40 years old, and they are in need of replacement.
“Our overhead lines are in very bad shape,” Becker said.
In addition to the electric lines, DMU is also putting in underground cable and phone lines.
“The cable and phone companies contracted us to do the work,” Becker said.
Cost and reliability
The cost to replace the existing overhead lines with underground lines is $11,800 per residential block.
If new overhead lines were installed instead, the per-block cost would be $7,482.
Although underground lines are more expensive than overhead lines, they are well worth it, according to Becker.
Contributions from the phone and cable companies help to offset the cost, as well.
“The amount of money DMU collects from the telephone and cable utility to pull their lines along with our lines is $4,175 per block,” Becker noted.
With that amount included, underground lines are $143 more than new overhead lines per block.
“There is a cost difference, but your reliability is way down with overhead lines,” Becker said.
In addition, underground lines are not affected by storms, tornadoes, and ice.
With the new underground cables, reliability will be further improved with a looping system.
“We are looping all our lines, so that if we lose a segment, we can back-feed from another source,” Becker said.
In the current industrial park, DMU put in a looping system with four ways to feed in power.
“In most areas, the minimum we want to have is two,” Becker said.
A few weeks ago, there was a small outage in which residents lost power for between a half hour and an hour and 15 minutes.
“If we would have had this in place, we could have had all our customers back on within a half hour,” Becker said. “It doesn’t prevent outages, but it will shorten the duration.”
Growth and voltage
The new underground cables will deliver power at 12,500 volts to transformers that serve existing residential and commercial customers along Highway 12. Previously, power output had been at 4,160 volts.
“We’re increasing the capacity on our conductors by approximately three times,” Becker said.
The underground cable effort is also making room for future growth on the north end of Delano.
“We’re basically preparing for a new industrial park, if and when it does happen,” Becker said.
Aesthetics and info
Improved aesthetics is another benefit of underground cables, according to Becker.
“So far, we’ve had very good feedback from our customers in locations where overhead lines have been removed,” he said. “It has improved the appearance of those areas considerably.”
DMU is currently working in various locations throughout the community.
Near Railroad Avenue, for example, underground lines have been installed, and DMU is waiting for the phone and cable companies to do a conversion.
When the conversion is complete, DMU removes the overhead lines.
Near 72nd Street SE, underground lines are also being installed.
Feeders are bored horizontally at about 5 feet below ground, with a directional drilling rig. According to a memo from DMU, the company’s equipment is capable of “steering” the drill head underground and clearing obstacles such as buried utilities, rocks, or tree roots.
After the hole is bored underground, the machine is used to pull black conduit, pipe, or wire through the same bore hole with a pulling pressure of up to 20,000 pounds.
For more information about the underground power cable project, call DMU at (763) 972-0557. The DMU web site is www.delanomn.us/index.html.