About the Project
The Queensborough Substation Project includes design and installation of the new substation which will provide a reliable power supply for the City of New Westminster (the City) and accommodate its future plan to convert the distribution system from 12kV to 25kV to meet growing electricity demand in the area. The new substation will alleviate the distribution back-up requirement and will provide back-up for the existing City’s RO2 (Royal 2) and BC Hydro’s NWR (New Westminster) substations. The substation connected load will be supplied by two 50 MVA 69/25/12 kV transformers.
SNC-Lavalin was the engineering consultant for the Queensborough Substation Project for The City of New Westminster responsible for Project Engineering Management, Detailed Design, Technical Specifications, Construction Specifications, and Construction Support. The Project was initiated to provide reliability and additional power supply to meet the growing demand for electricity in the area for the next 20 years. The scope of work included line interconnection with two 60 kV existing transmission lines, a 60 kV switchyard, two bays of 50 MVA power transformers, feeder sections, and a control building. SNC-Lavalin delivered a final design that met the project goals and provided contingency for the Queensborough substation to operate at 50% capacity in case of emergency. The design has provisions for future expansion of the existing power supply by 50%.
As part of the project, settlement analyses were conducted, and modelling confirmed that vertical wick drain should be installed to accelerate consolidation settlement of the soft soil to meet the project schedule. The application of prefabricated vertical wick drain was modeled, and direction to foundation and site grading design were provided. The outcome was published and presented in 75th Canadian Geotechnical Society’s conference in 2022. The impact of prefabricated vertical wick drain on improving the shear strength parameters of the soil had not been studied in detail before.
SNC-Lavalin developed preliminary design based on a BC Hydro study and design specifications in collaboration with the client. The study was based on the load forecast and the proposed location, and it confirmed power capacity and provided operation procedures and design requirements for the substation design. The preliminary design was reviewed and approved by the City and the relevant stakeholders. SNC-Lavalin finalized the design by conducting various electrical system studies to establish design parameters and technical specifications.
The site is underlain by peat which, when loaded, can result in large differential settlements. Both stone column and steel pile design options were investigated. As a result, +20 m—steel pile foundations were recommended for the heavy loads.
SNC-Lavalin held public consultation on noise and access and meaningful feedback was incorporated in the design. Ambient noise, transmission line structure locations, and substation fence line were adjusted to provide solutions like convenient access to the neighborhood facilities.
The site had limited space for construction layout and access as it is located within floodplain with poor soil conditions. All issues were resolved within budget while meeting schedule. For example, to address site constraints, SNC-Lavalin elevated the main site area above current grade and road elevations and added slopes to match existing grade. The control building elevation was increased and control cabinets and major equipment were raised to exceed the FCL so the station could continue functioning during flooding. This approach made the access to the easier for maintenance, increased the area available for substation use.
The site had limited space for construction layout and access as it is located within floodplain with poor soil conditions. All issues were resolved within budget while meeting schedule. Milestone were achieved despite the delays associated with COVID-19 early in the construction, when the work associated with the installation completed in November 2022 followed by testing and commissioning. The target In-Service Date for the project is on schedule for the end of April 2023.