Helicopter strings center line on tower for the new NV Energy power line as it begins to cross over U.S. Highway 93 in Dry Lake Valley. The 235-mile line will connect the Harry Allen Substation north of Las Vegas with the Robinson Summit Substation 20 miles east of Ely. (Dave Maxwell photo)

Helicopter strings center line on tower for the new NV Energy power line as it begins to cross over U.S. Highway 93 in Dry Lake Valley. The 235-mile line will connect the Harry Allen Substation north of Las Vegas with the Robinson Summit Substation 20 miles east of Ely. (Dave Maxwell photo)

One Nevada Transmission Line (ON Line) pulled power lines across U.S. 93 in Dry Lake Valley June 17.

The 235-mile long line will connect the Harry Allen Substation north of Las Vegas with the newly constructed Robinson Summit Substation, located 20 miles west of Ely.

The line will have a capacity of 500,000 volts and be able to handle about 600 megawatts of power.

Sturgeon Electric is providing construction services for the transmission line and Wilson Utility Construction is providing construction services for the Robinson Summit Substation.

About 850 towers, some up to 160 feet tall, have been installed, more than 3,000 anchors and 6,000 guy wires are being used.

Nearly 11 million feet of conductor wire is being strung, using specially trained helicopter crews to do the job.

NV Energy Public Communications Director Mark Severts said the work crossing U.S. 93 was the same as it is along the rest of the line, “to put a lead line, called a sock line, through the pulley system on the towers that will later pull the conductor lines into place.”

He said the helicopter pilot and ground crews work together to be sure the lead line slips into place in the pulleys as the helicopter hovers overhead. Then the helicopter moves onto the next tower.

Severts said the towers have five lines, and the helicopter moves along, stringing one line at a time, covering about five or six miles per day. The lower three lines are the conductor lines. The upper outside lines are static lines, in case lightening might hit one of the towers.

“The helicopter strings one line, then goes back and strings the next line. Doing the center line is the most difficult.”

The pilot hovers over the work site, virtually hanging out the door and maneuvering the helicopter in just the right way to string the lines into a small trap door on each pulley that snaps the line into place.

“Helicopters are used,” Severts said, “because it would be just too slow and costly to have to have someone climb the towers on the outside, and would still have difficulty stringing the center line below the cross arm, even on the traditional H shaped poles.”

Occasionally, Severts said, inspections, and/or small repairs, need to be done as the line is being placed, and the helicopter will take a man up in a specially designed harness in a bucket chair for a close up inspection of the line and the pulleys. “Much easier and faster than trying to get a large crane type vehicle out there on uneven ground,” he said.

Later ground crews come along and pull the conductor lines through the towers and make sure all the extra swag is removed and the lines have the proper ground clearances.

When completed, Severts said, “The ON Nevada project will connect NV Energy’s northern and southern service territories for the first time ever. It brings renewable energy from wind projects up in White Pine County and major solar projects near Tonopah to the Las Vegas area. From solar projects in Las Vegas, that power will then be able to flow north and toward Reno and Winnemucca.”

“It enables NV Energy to be much more efficient,” he said. “If we have a power plant problem in the south, we can use northern resources, and vica versa, instead of needing to buy on the open market, which can be very expensive on a hot June or July afternoon.”

Future plans from LS Power, the primary owner of the new line, hope to eventually tie in with power from dams along the Snake River in Idaho.

NV Energy has a number of renewable energy sources, most located in the western part of the state, and a few in California.