Public Service Co. of Colorado, a unit of Xcel Energy, won permission October 8 to increase the height of several 115-kV transmission structures along the portion of a line that extends from Poncha Springs in Chaffee County, Colorado, to Caàƒ±on City in Fremont County.
“There are currently 113 towers within Chaffee County along this line [and] they’re increasing the height of 12 of them to maintain ground clearance,” Don Reimer, Chaffee County development director, told TransmissionHub October 10.
Following a 2008 NERC alert regarding clearance issues, the utility performed assessments using LIDAR technology and identified some 40 power poles that needed to be replaced due to inadequate surface clearance along the entire stretch of the 1958-vintage line, which runs about 52 miles and connects Poncha Springs in Chaffee County with the Malta substation in Lake County, Colo.
“We’re going back in and replacing structures or adding additional height to them to ensure adequate clearance to meet requirements,” Betty Mirzayi, manager of regional transmission initiatives for PSCo, told TransmissionHub October 11.
Due to the current maximum tower height of 60 feet, a special land-use permit called a “non-conforming use permit” was already required for the structures in Chaffee County. Raising them to as much as 80 feet required expansion of that permit.
Chaffee County commissioners approved the expansion of the use permit after hearing from utility representatives, including an Xcel Energy engineer who told the commissioners that the 2003 East Coast blackout was an example of what can happen when power lines come too close to vegetation, Reimer said.
While the use permit is the last approval that must be obtained from Chaffee County, additional approvals must still be obtained.
One of the towers for which the height will be increased is near Harriet Alexander Field, a small general-aviation airport near the town of Salida, Colo. Reimer recommended, and the county commissioners concurred, that PSCo obtain an airspace clearance from the Federal Aviation Administration (FAA) before starting construction work on that tower.
However, more than 4,000 FAA safety inspectors, airline-oversight staff, traffic-control support personnel and others, including those who respond to news media inquiries, remain furloughed as a result of the ongoing government shutdown. Accordingly, additional details regarding the need for an airspace clearance were unavailable as of press time October 10.
After leaving Chaffee County to the northeast of Salida, the line continues to Caàƒ±on City in Fremont County, where special permits are not required.
“In Fremont County, the line is over mostly federal recreational and state lands,” Mirzayi said. “Our understanding is that the type of work that we’re doing does not require the same type of permitting in Fremont County as in Chaffee County.”
The project is scheduled to be completed in 2014.