Sandwell's skills in this field include power system analysis, transmission line route selection, tower site layout, and line optimization. In the area of power line design, we have engineered 300 kV transmission line towers, 34.5 kV woodpole lines, as well as a myriad of cable tray, conduit and buried duct industrial distribution systems.
British Columbia Hydro & Power Authority, Vancouver, British Columbia
230 kV Transmission Network Supply Development
The Metro Vancouver 230 kV transmission system comprises 21 substations and 34 overhead line or underground cable circuits. With sub-consultant Siemens, Sandwell reviewed the system development plans, providing B.C. Hydro with an independent "second opinion" for use at future regulatory hearings.
In the built-up areas, the network includes 85 km of underground 230 kV cable; more than any other city except Paris. Much of this cable is now over 40 years old and is nearing the end of its useful life.
Sandwell modeled the entire system, measured its reliability and discovered the vulnerability of the supply to the downtown area. Our 20-year plan provided cable replacement and stage development options, along with costs, schedules and risks. B.C. Hydro is now constructing a new 230 kV cable circuit to downtown Vancouver to be in service by late 2004, at a cost of $48 million.
Alcan Smelters and Chemicals Ltd., Kitimat, British Columbia
Transmission tower replacement
River scour threatened to undermine the foundations of two transmission towers supplying Alcan's aluminum smelters at Kitimat, British Columbia. After conceptual and detail design, with Sandwell's construction assistance, pipe-pile foundations 30 meters deep were driven to support a new, taller tower, allowing two existing towers to be dismantled. The work was completed without interrupting power to the smelter.
Alcan Smelters and Chemicals Ltd., Kitimat, B.C.
Transmission line re-routing
Energy for Alcan's aluminum smelter in Kitimat, B.C. is supplied by a 100 km long, 300 kV transmission line traversing the rugged terrain of the Coastal mountains from the Kemano generating station. The section of the line that ran through Kitimaat Village was rerouted to a new 5 km long alignment on the mountainside above the village. Tower sites were scarce and many spans are close to 1,000 m., Because of the terrain, all construction was done by helicopter. Construction was completed without interrupting the supply to the smelter.
