Transmission Line Structure Replacements

Withheld Upon Owner Request

Scope of Work

Cianbro replaced 230 kV H-frame structures and 115 kV single-pole, braced-post-insulator structures. The existing structures were primarily wood pole structures, which were replaced with steel poles. These replacements were performed for two primary reasons; NERC ground clearance requirements, and standard maintenance purposes. The replacements were performed using two methods. The first method was an in-place replacement, which involved suspending the cross-arm, conductors, and static wires from a crane, while the old poles were removed and new poles were set. Then the cross-arm, conductors, and static wires were reattached to the new poles. The second method was an offset replacement, which involved building a new structure entirely, attaching the conductors and static wire to the new structure, and removing the old structure.

Project Details

  • Replaced (89) 230 kV H-frame tangent structures
  • Replaced (7) 230 kV 3-pole running angle and dead-end structures
  • Replaced (26) 115 kV 1-pole tangent structures
  • Replaced (4) 115 kV 1-pole running angle structures
  • Installed 226 poles
  • Installed (95) 30 inch diameter pipe piles, either 12 feet or 20 feet long
  • Worked on structures spread out over 40 miles of right-of-way
  • De-energized all lines while structures were replaced

Lean, Innovative, and Unique Project Solutions

The project schedule involved three 1-month outage windows, requiring approximately 40 structures to be replaced per month. Outages were shortened due to weather conditions.