RCU Solutions | Rail services

Guildford Substation Power Supply Enhancement

  • Client: Kier Infrastructure
  • Project Type: Electrical installation
  • Sector: Rail
  • Project Commenced: January 2020
  • Project Completed: May 2020
  • Location: Walnut tree close, Guildford
Anode frame containment showing cables from rectifier unit in DC building to new transformer rectifier within rainwater shelter
New rainwater shelter and negative busbar shown here
Containment for Anode cables


Guildford Substation was one of several power supply enhancement projects for Network Rail in the Wessex region which included installation of an additional DC module with interconnecting DC cables onto the existing switchgear in the DC main building with a busbar modification. The project also involved associated ETE works including track disconnector switches, an additional HV breaker and interconnecting HV cables between the primary and secondary HV modules.

The existing transformer rectifier was upgraded to 2x larger 3MW rectifier transformers and a new rectifier module. The remote terminal unit (RTU) was also replaced. These works were all completed by the previous contractor, except the final phase which was the replacement of the transformer and rectifier 1 on the main DC building, which was delivered by RCU Solutions. Due to the limited number of possessions available at Guildford, this installation and commissioning was delivered to a very tight programme by RCU Solutions.

With the previous contractor now defunct, principal contractor Kier was appointed to complete stages 3, 4 and 5 of the staged operations. This was to de-commission the existing transformer rectifier and rectifier unit 1 and install the new transformer and rectifier unit on the DC building and commission into service.

RCU solutions was contracted to complete the electrical installation and commissioning elements of the work associated with the remaining works required to replace transformer rectifier 1. This included the installation of a new R1 main DC circuit breaker (DCCB) and associated separate wall-mounted frame leakage panel. A busbar modification on the existing DC switchboard was also completed along with the LV lighting and power in the newly erected transformer shelter.

Busbar modification in existing old RJR DC switchgear
New main R1 DCCB and transformer rectifier unit
HV terminations on rectifier transformer

The scope of works completed by RCU Solutions included:

  • De-commissioning of redundant transformer rectifier 1 and associated cables, equipment and containment
  • Installation of equipment including new R1 main DCCB, rectifier unit, frame leakage unit and LV equipment in the rainwater shelters
  • Installation of containment including Unistrut, ladder racks and cable trays and conduit
  • Installation, termination and testing of LV, control/ancillary and earth cables
  • Installation and termination of HV cables
  • Installation and termination of DC cables
  • Pre-commissioning and commissioning of all equipment and cables

“The electrical installation and commissioning was the most complex phase of this project, but our team delivered it safely, efficiently, on time and to a high standard, with a prompt handover completed as per the client requirements. Well done to the project team for a great delivery.”

Genero Henderson-Park Delivery Manager, RCU Solutions

Door to new rainwater shelter with PIR, light and signage
LED Lighting in rainwater shelter
Tool TX and fused spur connection unit in rainwater shelter

Having worked with Kier Infrastructure on several projects, they are confi dent in our ability to deliver their projects on time and within budget. The Kier project management team expressed their appreciation for delivering the complex works to a high standard, safely and efficiently.