Richborough 400kV GIS Substation

Connecting the National Grid Network and the NEMO link between the UK and Belgium

Innovative solutions overcoming material restrictions and challenging soil conditions

Engineers on site throughout construction enabling fast decision making

Client: Morgan SindallNational GridInternational OEM

Connecting point

A challenging and complex project, the new 400kV, eight bay Double Bus substation at Richborough provides the point of connection between the existing National Grid network and the NEMO Link HVDC interconnection between the UK and Belgium. To enable this it also saw the construction of a new 400kV overhead line (OHL) between the new substation and Canterbury North 400kV substation.

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

  • Design of the new GIS building and two SGT bunds and associated oil drainage system
  • Foundation design for the OHL’s gantry, CSE, AIS and GIB support structures and the Mechanically Switched Capacitor (MSC)
  • Design of surface water drainage system, category two perimeter security fence and new access roads
  • Design of 400kV and 132kV underground cable circuits and LV cables, communications and services duct systems 

Flexible designs

With challenging soil conditions and restrictions on the type of materials able to be used in some areas of the site, our engineers created flexible and innovative designs. For example, fibre reinforcement was used on the foundations within the MSC area to avoid the electrical field inducing circulating currents. Being present on site supporting the contactor throughout enabled our engineers to make fast decisions when challenges arose. When the piling contractor came across unexpected ground conditions whilst installing the original CFA design piles, BakerHicks’ engineers were able to react quickly and amend the design to the new driven pile type more suited to the ground. It also enabled suitable changes to the foundation type to be made on site during the construction phase as the issues arose, keeping the project on track.

With the new substation project providing the connecting point between multiple projects, the design had to be carefully coordinated. Our engineers were proactive in coordinating the interfaces with the NEMO Link, the Static Var Compensator and the connection to the Canterbury North, ensuring everything was correct and there were no clashes. To manage the international link to the NEMO HVDC interconnector project regular design coordination meetings and teleconferences were held throughout the HV cable design process to manage the international link. This enabled the coordination of the two teams and design deliverables as well as the interfaces between the cable system and the GIS equipment in the converter station, resulting in the successful design of a unique and innovative combined GIB/CSE structure.

Completed safely and to programme, the new substation provides a connection point for the NEMO Link, helping to secure the electricity supply for both the UK and Belgium.