A newly installed underground transmission cable running 10.5 km long under the streets of Edmonton is powering the core of the city. The new line is designed to accommodate rapidly growing electricity demand resulting from Edmonton's high growth rate, and provide additional security of supply to Edmonton's city center. The 240-kV cable runs underground from the Castle Downs Substation at 16253 97 St. to the Victoria Substation at 10520 104 St.
The continued prosperity of the Edmonton city core depends on a secure and reliable supply of electricity," said Guy Bridgeman, EPCOR Senior Vice President. "Downtown Edmonton continues to grow, and this project will ensure we can support that growth long into the future."
"We congratulate EPCOR on the successful completion of this project," said Neil Millar, Vice President Transmission, Alberta Electric System Operator. "As is the case in many areas of the province, this transmission upgrade is critical to ensuring the long term reliability of the electric system and to meeting customers' growing demand for service. We appreciate the amount of teamwork and cooperation demonstrated by EPCOR on this project."
The three-year initiative involved extensive public consultation, a major directional drilling operation, and trenching and cable pulling along busy roadways.
The underground cable runs 2 m under Edmonton’s streets, and more than 6 m deep in some locations between EPCOR’s Castle Downs and Victoria substations. Approximately 30 km of cable (three times the length of the route) was installed and spliced together.
EPCOR used innovative construction techniques to minimize disruptions to neighboring areas, including Horizontal Directional Drilling (HDD), a trenchless method of installing pipes along a pre-determined path without cutting through pavement. EPCOR used HDD to cross under the CN Rail Yards and Yellowhead Trail.
A total of 17 underground concrete vaults were installed over the total length of the route. The vaults were used for splicing the cables and will be used for future maintenance and testing of the cables.
EPCOR’s Victoria substation was expanded to accommodate the new 240-kV feed to allow for future supply of Edmonton’s growing downtown, including the EPCOR Tower currently under construction. Originally, another location had been chosen as the end-point, but EPCOR changed plans in response to stakeholder feedback.
Construction was undertaken over a 1.5 year period beginning in March 2007.