Canterbury 400kV GIS Substation

New 400kV GIS substation constructed within confines of the existing site

Enhancing system management through installation of new Shunt Reactor

HV and LV cabling safely routed through existing site 

Client: National GridInternational OEM

Underground cabling

A complex and innovative project conducted within the spatial confines of the existing substation, the extension of the 400kV Canterbury North substation will facilitate the connection of a new HVDC link between the UK and Belgium. It will see 400kV underground cables routed through the existing substation site to the new GIS substation.

BakerHicks provided HV cabling design, civil and structural engineering and architectural services on this project. Key services provided included: 

  • Electrical design and layout of HV cable route, including supporting calculations for HV cable pulling and installation plus extension of the earth mesh
  • Design of new GIS building, Shunt Reactor’s bund, Cable Sealing Ends, OHL gantry foundations, surface water drainage system, LV cables, communications and services duct systems, perimeter fence
  • New access road design and modification to existing roads
  • Surveys and assessments of existing foundations 

Space efficient designs

With limited historical information and the possibility of unknown redundant foundations on the site, flexible designs and fast decision making were imperative. Our engineers conducted additional surveys to establish the location of underground services and bring the hazard plan up-to-date, enabling them to safely route the 400kV cabling through the existing substation compound. New compact 400kV cable sealing ends terminations were also designed to meet the requirements imposed by limited space on site and design interfaces with GIS suppliers and primary system designers.

An efficient design, the new Shunt Reactor enhances the system management of the area ensuring effective operation during low demand periods when additional inductive loads are required to maintain system voltage levels within the normal range. Our engineers developed the design and the installation strategy for this and the associated 400kV cabling that connects the two double circuits to the new GIS building. They also designed a cast in-situ continuous HV cable and communications trough with bespoke covers, which was especially challenging due necessary changes in route being made throughout the design and construction period.

The project design was completed to schedule and is due for completion mid-2018, it will deliver the infrastructure needed to connect the Richborough Overhead Line and provide another HVDC connecting line between the UK and Belgium.