Site Power HV/LV Electrical Design

The HV/ LV electrical design is essential to develop a robust and safe electrical distribution network within the Tunnel Launch Compound (TLC), the STP, SXB, SMT areas within the Temporary Construction Area (TCA) and the Ancillary Construction Area (ACA) to support tunnel construction at the SZC site. The network will be required to distribute power to the following areas and equipment:

Underground: Tunnel boring machines (TBMs), Slurry pump system Underground Conveyor belt system Ventilation system Lighting & Communication networks Ancillary tunnel construction equipment

Overground: Ventilation system Cooling water system Overground conveyor belt system Overground slurry pump system Compressed air system Grout batching plant Dewatering system & water treatment plant Gantry cranes Site lighting, access control & communication systems Office building/ welfare Ancillary site activities

Electrical loading details of the equipment listed above will be collated and provided by CWA to the selected electrical design engineers. The design will be required to comply with current British Electrical safety legislation.

Key Deliverables: HV network design - Provide the design for the distribution of the 11kV network that feeds the TLC, TCA & ACA compounds complete with associated switchgear, cable sizing, cable routes and containment systems. Provide protection settings of circuit protective devices for safe disconnection of the supply under fault conditions. Stage 4 drawings complete with associated schematics to be provided of proposed cable routes, ducting sizing/ routes, substation locations. The design will need to be agreed with the CWA/ Sizewell site team to ensure power demands and circuit configurations are compatible with the wider HV network on site.

Substation design - The design and specification of the substations complete with earthing design to distribute and transform where necessary the main 11kV supply that will be used to supply the above listed compounds. Where LV (690v/400v) supplies are required, suitably sized transformers to be specified to provide sufficient power for the supplied equipment. Stage 4 drawings complete with associated schematics to be provided of substations.

LV Network - Provide the design for the distribution of LV network to supply required equipment/ plant with associated switchgear, cable sizing, cable routes and containment systems to required areas of distribution. Provide protection settings of circuit protective devices for safe disconnection of the supply under fault conditions. Stage 4 drawings complete with associated schematics to be provided of proposed cable routes, substation/feeder pillar locations, MDU sub main distribution locations.

Site Lighting - Provide site lighting design to provide adequate lighting for site activities. Stage 4 drawings complete with associated schematics to be provided of lighting locations and specifications.