Northwest Transmission Line

Client: BC Hydro
Completion Date: 2014
Location: Terrace, British Columbia

Summary

The Northwest Transmission Line (NTL) project includes a 287-kV transmission line that runs 342 km from Skeena Substation (near Terrace, British Columbia) to a new substation near Bob Quinn Lake.

The NTL project helps BC Hydro meet BC Energy Plan objectives, including grid expansion, energy conservation, innovation and enhanced reliability. This new line provides a reliable supply of clean power to potential industrial developments in the area, provides a secure interconnection point for clean generation projects and enables northwest British Columbia communities to access the electricity grid instead of obtaining power from diesel generators.

Services

  • Project management
  • Construction management
  • Preliminary and detailed transmission engineering
  • Procurement
  • Transmission line construction
  • Access road construction management
  • Right-of-way clearing management
  • Subcontractor and consultant management
  • Schedule control
  • Cost control
  • QA/QC management

Background

Burns & McDonnell teamed with Valard Construction, Calgary, Alberta, to form a joint venture, Valard-Burns & McDonnell. The team provided full engineering, procurement, permitting support and construction. The project traverses the extremely rough terrain and varying environmental conditions of northwestern British Columbia and includes major river crossings at the Skeena River, the Bell River and the Lava Lake Provincial Park. The line includes spans in excess of 1,000 meters. Helicopter construction of portions of the line, including tower erection and conductor installation, was required. Additionally, the line crosses sensitive environmental areas and reserves, requiring extremely close coordination with several permitting agencies.

The remote location of the project also required detailed coordination of tower, material and conductor deliveries to ensure on-time availability to support construction. The remoteness of the line required use of labor camps to support construction, necessitating close management and scheduling of construction activities.

The transmission line design also required a detailed terrain hazard assessment to evaluate areas of landslides, avalanches and scour. Additionally, the line was subject to extreme ice loadings due to high elevations and the extremely large snowfalls in the region. The line also traverses seismically-active areas with liquefiable soils that require consideration during structure spotting and foundation design.

The project also included a requirement that Valard-Burns & McDonnell provide management of BC Hydro direct-award contracts for right-of-way clearing and access road construction. These direct award contracts were given to aboriginal First Nations in British Columbia. Valard-Burns & McDonnell also committed to and is using First Nations labor for specific construction tasks and First Nations suppliers, when available.

Features

The NTL project consists of a single-circuit, 287-kV guyed lattice tower transmission line with two-bundle 1,590 kcmil conductor. Valard-Burns & McDonnell's scope of work included:

  • Preliminary and detailed transmission line design
    • Structure spotting
    • Detailed construction drawings, including plan and profile drawings
    • Lattice tower and tubular steel structure design
    • Steel grillage design
    • Foundation design
    • Hardware and assembly design
    • Conductor evaluation and selection
    • Fiber optic shield wire evaluation and selection
    • Fiber optic regeneration site selection
  • Procurement of all materials
    • Lattice towers
    • Tubular steel structures
    • Steel grillage foundations
    • Conductor
    • Fiber optic shield wire
    • Hardware and assemblies
    • Fiber optic regeneration site equipment
  • Construction
    • Foundation installation
    • Lattice tower assembly and erection, including helicopter construction
    • Tubular steel pole assembly and erection
    • Hardware and assembly installation
    • Conductor and fiber optic shield wire installation
    • Construction of fiber optic regeneration sites
  • Project and construction management
    • Subcontractor/subconsultant management, administration and coordination
    • Schedule management
    • Cost control
    • Quality assurance/quality control management
    • Material management
    • Management of right-of-way clearing and access road construction
    • Management of right-of-way cleanup and restoration
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