Konecranes upgrades crane for Georgia Power
Difficult installations are routine for Konecranes, but an ongoing crane upgrade project at the Tallulah Falls hydroelectric plant is truly something out of the ordinary.
Global lifting leader Konecranes is performing a series of crane upgrade projects for Georgia Power’s North Georgia Hydro Group along a 28-mile stretch of the Tallulah and Tugalo rivers. The seven plants use the natural energy of falling water to produce efficient and economical electricity. Tallulah Falls, the oldest and largest of the group, first began operating in 1913. Konecranes is currently upgrading the 60-ton primary maintenance crane at the Tallulah Falls plant.
“The terrain that made this area advantageous to develop hydroelectric power over a hundred years ago is making our job extremely challenging today,” says Dan Devore, district operations manager for Konecranes Atlantic District.
For either men or equipment, there are only two ways to reach the Tallulah Falls hydroelectric plant: by boat, or on a trolley suspended by wire rope that drops approximately 1,000 feet from the mountain top down to lake level at the bottom of a ravine. Konecranes has removed a trolley car built for moving people so they can use a 60-ton capacity maintenance cart to transport a mobile crane and new components for the crane rebuild. Before committing to this scenario the Konecranes team considered several other options, including ferrying components to the site by helicopter.
The original DC-powered Shaw crane was upgraded with a custom Konecranes CJ-series 60-ton AC-powered trolley with a 25-ton auxiliary hoist. The new trolley and hoists feature variable frequency drives and convert the cab-operated crane to radio controls that can be operated from the ground. Konecranes also replaced aging wooden catwalks with modern steel versions, an important safety enhancement. The crane is key equipment for turbine maintenance outages.
According to Georgia Power’s Project Manager Frank Payton, the original hoist machinery, over 100 years old, had serious reliability issues. Rheostats used to control speed were worn out and most electrical parts were obsolete and unavailable.
“We were still able to operate the crane, but it was becoming so unreliable that we no longer trusted it from a safety standpoint,” said Payton. “The new trolley and hoist are radio-controlled and much easier to operate. The variable frequency drives allow us to make precision lifts setting turbines and rotors with just a few thousands of an inch clearance with no problems. These controls give us an important safety advantage as we are able to precisely manage the speed of travel and hoisting loads.”
An earlier rebuild performed by Konecranes at North Georgia Power’s Nacoochee plant gave Payton’s team an opportunity to road-test the improvements before purchasing a similar upgrade for Tallulah Falls.
The logistics for the rebuild were complicated. Because of the difficult access and limited work area, it was feasible to bring only one mobile crane down the mountain. Removing the personnel cart gave the 18-ton capacity mobile crane room to drive off the maintenance cart directly onto the pavement, where it was used to unload components of the new trolley, move them into the building and install them. Konecranes was prepared to build a monorail construction crane if it was needed, but instead decided to further disassemble the new hoist and install it in pieces, 60 feet above floor level.
“Even after some disassembly, the lightest we could make the new trolley was 5,800 pounds,” says Devore. “After considering several options, we used the mobile crane to dismantle the old crane and put the new trolley and hoist up on the rails.”
According to Devore, Tallulah Falls Plant Manager Barry Brookshire wanted to keep the nostalgic look of the hundred-year-old facility, which called for a hoist that combined big, beefy last-forever appearance with actual robust performance. Konecranes custom CJ design fit the bill.
“Georgia Power hopes this hoist will last for another hundred years, so they won’t have to deal with the logistics of this project again,” said Devore.
Georgia Power is partnering with Konecranes in an ongoing series of crane upgrades for the North Georgia Hydro Group. Tallulah Falls was the second of seven projects planned.
“We have worked with Konecranes for years on inspections, and always had good results,” said Payton. “We have no reason to partner with anyone else. They knew our facility and our equipment, understood what our needs were and were able to supply those needs for us. The logistics were extremely difficult, but Konecranes finished the job on schedule.”
Staging on the Tallulah Falls replacement began the third week in April. Load-testing and handover of the crane were completed at the beginning of June.