One of Canada’s largest utility companies, sought to replace the 91km of electrical transmission lines in the Ontario community of Petawawa. The lines had originally been built in the 1940s, so in the interest of increasing power efficiency and reliability, the utility decided full-scale replacement was the best option. Project execution would consist of six phases, spanning three years, involving install of 28 new composite structures and shield wires and also restringing conductors. A significant challenge of this project was the prospect of keeping all customers powered for the duration without interruption. Several approaches were considered – from load transfer, to multiple outages, to building a by-pass or setting up a temporary grid on demand. With any of these solutions, there were several key risks to mitigate:

• A radial feed with zero

• Losing the reliability and customer satisfaction for which the utility company is recognized

• Delaying the project due to the regulatory approval process of construction projects

Ultimately, the goal was to find the right solution to keep Petawawa powered while the Utility Company completed its capital grid hardening program as quickly as possible to achieve in-service agreement (ISA) goals and minimize customer impact.