The Ampjack Team completed a 220-kV structure for Southern California Edison located in the Angeles National Forest addressing multiple challenges under extreme conditions.
The tower raise parameters involved:
- 220-kV single-circuit tangent tower with bundled conductors
- 15’-0 tower raise in total
- Custom scaffolding was flown in and installed as a working platform due to very challenging terrain: extremely uneven ground and nowhere to land or spot men and/or equipment
- The structure to be raised was located at the top of an inaccessible mountain peak situated between 2 dead-end structures with extremely unbalanced spans of approximately 100 ft and 1,300 ft in each direction. To complete the tower raise and not induce over-tensioning of the conductors, tension mitigation was integrated into the lift sequencing in the form of dead-end hardware adjustments at the overhead ground wire and all phase conductors. Final wire tension mitigation was completed at each of the 2 adjacent dead-end structures to complete the tower raise process
- Ampjack Crew size - 13, Traffic Control - 4, Helicopter crew - 2, Scaffolding crew - 3
- Total days to perform this raise: 6 days (3 days once AMPJACK® equipment was on site and wire tension mitigation was completed)
- Ampjack Engineering complexities: Integrated work procedures to manage wire tensions during the lift sequencing and determining final dead-end hardware assemblies to get the correct final conductor length ensuring clearance upgrades and proper final tension on the adjacent spans
- All crew members, AMPJACK® components, equipment and tooling were air (helicopter) lifted onto this small platform as well as onto the adjacent structures
Ampjack said that with more than 750 tower raises performed to date, and several tower raises currently under review for execution, it hopes that this solution brings the industry added value on grid resiliency as utilities are looking to optimize existing assets for current/future demand in a cost-effective, eco-friendly, and accelerated manner more than ever.