As one of the top three electric co-ops in the state, Rolling Hills Electric Cooperative, Inc. provides power to members in 16 counties, across about 3,800 square miles, in rural North Central Kansas.
Rolling Hills was formed in 2002 when NCK Electric Cooperative in Belleville, Jewell Mitchell Electric Cooperative in Mankato, and Smoky Hill Electric Cooperative in Ellsworth consolidated. The co-op distribution network includes about 6,383 miles of line, a little over 11,000 meters and 125,000 poles, both steel and wood.
Melvin Jeardoe, operations manager for the co-op’s District 3, recalls, “We started replacing wood poles with steel poles around 1998, primarily because of the longevity and durability of the steel. They last longer, require less labor to install and are more resilient in significant weather events such as ice storms with high winds.”
Rolling Hills initiated an extensive replacement of wood poles with steel poles following two major ice storm events, which occurred in 2007 and 2009, causing in excess of $35 million in damage. Both of these events qualified as FEMA natural disasters.
“We lost a lot of poles during those storms, and with help from FEMA funding, put together a plan to replace downed wood poles with steel poles at critical locations,” says Jeardoe. “We replaced the poles at major intersections and at the middle of every line mile to act as a storm break pole. We also use steel poles with double guy wires for extra strength where the pole sits at an angle or at a junction pole.”
Because steel poles are more conductive than wood poles, the co-op moved to fiberglass pole top pins and extension links. They use fiberglass pins at the pole top for greater insulation and a fiberglass extension link on any taps or deadend taps off of the steel poles. Jeardoe and his team have found, along with fiberglass crossarms, the fiberglass components create a very good BIL rating, which prevents flashover.
In total, the co-op replaced poles across about 450 miles of the network during the FEMA project which concluded in 2015.
When asked about the resilience of the steel poles, Jeardoe points to the most recent ice events: “The ice load broke three wood poles, but the closest junction pole held. In another case, a car hit the guy wires and the steel pole bowed over, but didn’t break. For the repair, we straightened the pole and reattached the guy wires.”
Rolling Hills has also evaluated its older steel poles for corrosion. Jeardoe says, “We recently removed a galvanized steel pole first installed 15 years ago with a polyurethane coating which did not extend to the base of the pole. Still, only surface corr0stion appeared at the base of the galvanized steel. We brought it to the pole yard and scrubbed it with a wire brush—99% was surface corrosion. Back in the 1990s, steel poles were not coated all the way to the bottom. For added protection, we now specify a polyurethane coating extending up from the base of the pole to about 18 inches above ground level for optimal protection against corrosion.”
Today, the co-op has about 1500 steel poles located at critical points—and the benefit of those poles is visible in measurable savings. Jeardoe concludes, “Ten years ago, line crews would put in an average of 15-20 hours overtime every week handling outages and maintenance work. Today, we might go three weeks without any overtime. We know that the initial cost of steel poles is higher than wood poles, but the life-cycle benefits we gain in a more resilient, less labor-intensive network more than make up the difference.”
In 2015, the USDA Rural Development Program awarded a $17 million loan to Rolling Hills Electric Cooperative to build or improve 197 miles of transmission and distribution lines and make other system improvements, which will likely include more steel poles.
Sources and Related Information