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3 x 66kV HV Cable Circuits + Additional Scope Post Fire
United Kingdom
Cable Rating, Routing. Feasibility
Scottish Southern Electricity Networks
All works completed in-house
A substation fire mid-feasibility forced a significant redesign of a congested 66kV cable routing.
Groundline was appointed to deliver feasibility design for five new 132kVrated cable circuit incomers (operating at 66kV) connecting existing AIS switchgear to a proposed new 23-way 132kV GIS switchboard at North Hyde BSP Substation. During feasibility, a significant fire damaged several pieces of apparatus and required the GIS switchgear to be relocated to a different building - fundamentally changing the cable routing requirements and adding scope midproject.
Groundline absorbed the additional scope, redesigned the affected routes, and deployed on-site engineering support to manage a highly congested underground environment.
The revised cable routes were identified as running through a heavily congested area of existing underground infrastructure, requiring a GPR survey to capture depths, locations, and routes of existing services before design could be finalised. Groundline produced a full suite of deliverables across both the original and revised scope, including cable rating and terminations reports, route and profile drawings, joint bay layouts, bonding schedules, induced voltage and EMF assessments, buried services assessments, installation methodology, and detailed design estimates. Design engineers with construction experience attended site to provide direct input on construction risks and practical routing challenges.
Continuous design support through a live and evolving project, keeping feasibility on track despite unplanned scope change.
By responding quickly to the post-fire redesign requirement and maintaining momentum through site attendance and additional cable design, Groundline enabled the project to progress without losing programme. The GPR survey approach de-risked the congested new route, and the combination of design capability and on-site engineering presence ensured the client had practical, buildable solutions as the substation layout continued to evolve. The project remains ongoing as of April 2025.
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