The maintenance map; System-aging study shows 60 percent of lines have been replaced since 2000
The Lorain-Medina Rural Electric Cooperative Operations Department mantra is rather simple: Preventive maintenance is the cheapest form of maintenance.
It pays off in system reliability and member satisfaction. Fewer and shorter outages normally makes for happier consumers. To meet those expectations, a strategic plan needs to be in place and implemented.
the LMRE engineering team of Brad Warnement, Patrick Pifher and Lynn Hill have conducted and updated a system-aging study to determine the age of lines throughout the cooperative's service territory.
Pifher presented the latest study to the LMRE Board of Trustees at its December meeting. The original system-aging study was completed and presented to the board in 2013.
The study allows the management team and the board to forecast future construction and replacement projects.
"Line construction is not going to get any cheaper," LMRE General Manager Markus Bryant said. " Lines built in the 1960s certainly will cost more to replace 50 years later. We need to plan for that."
The cooperative was formed in 1935, and lines were first installed in 1936. The system has since grown to over 1,500 miles of line in five counties.
Over time, the poles, cross arms, conductors and other equipment initially installed in the 1930s were replaced. Sometimes, equipment was replaced because the cooperative's loads grew to levels requiring larger conductor, bigger, stronger poles, three-phase electrical service instead of single phase and so on.
Some equipment was replaced due to storm damage. About 60 percent of the cooperative's lines have been replaced since 2000, thanks in large part to the devastating 2005 ice storm. As a not-for-profit electric cooperative, LMRE qualified for a Federal Emergency Management Agency (FEMA) grant to replace 75 miles of line. Within four years, the cooperative spent $2.66 million replacing these damaged lines, with FEMA supplying 75 percent of the cost, or $1.99 million, and LMRE contributing the remaining $650,000.
Today, about 7.5 percent of the lines date back to 1969 or earlier.
Other equipment, though, was replaced simply because wooden structures and conductor materials (the wire that carries electricity across an electrical distribution system) age and degrade over time because of operational, weathering or other environmental factors. For one reason or a another, after about 40 years or more the service in the field, much of the cooperative's overhead system (the poles and wires seen along the road) had largely been replaced with newer structures and conductors by the mid-1960s and 1970s.
LMRE recently analyzed the age of the entire overhead distribution system to prepare for planned replacement of aged overhead distribution conductor. "A systematic replacement plan is not only more cost-effective than only making repairs or replacements during emergencies, but it also results in more efficient and reliable system operation over the long term," Pifher said.
Generally speaking, poles and other wooden structures typically last in the field for about 30 to 40 years before deterioration requires that they be replaced. Metal conductors can last from 50 to 60 years.
The cooperative today maintains an aggressive pole-testing program. Lorain-Medina regularly tests poles throughout the entire system every five years, replacing them and other wooden structures where testing shows significant loss in strength and/or integrity. The Rural Utilities Services, an agency under the U.S. Department of Agriculture that provides federal loans to cooperatives nationwide, requires cooperatives to test their poles at least every 10 years. If poles can be identified that are questionable in strength and then replaced on a normal schedule, outage times are minimized. In addition to testing poles, the contractors inspect all equipment for hazards, concerns or possible repairs along with adding missing guy markers or replacing them as necessary.
The table below shows the results of LMRE system testing over the last seven years: The percentage of rejected poles has remained consistently low, and the cost to inspect each pole has risen less than 10 percent since 2008.
Pole inspection history
|Test Year||Poles Tested||No. Rejected||% Rejected||Total Cost||
Cost to test