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Case Study

RJ Power North has successfully completed a new 11kV substation upgrade project on behalf of Calor Gas.

In advance of the works, a pre site visit and meeting was conducted by our Business Development and Operations team. All associated project documentation and site notes were collated and a Tender document was duly submitted.

Following successful award of the tender, both RJ Power North’s Senior Authorised Person and Project Manager held further site visits, meetings, undertook final checks and completed the associated paperwork for procurement of the necessary equipment and materials. Detailed planning including Risk Assessments, Method Statements and hour by hour work plans were produced and forwarded across to the client for approval in advance of the works commencement.


RJ Power North Limited completed the project over 5 working days, across two separate phases:

Phase one of the project was to install the new HV Transformer on to a newly formed raised concrete bunded plinth located externally to the 11kV substation. The new 11kV switchgear was installed and mounted on to a raised steel structure within the 11kV substation.

A cable containment system was installed to allow new HV and LV cable routes to be accomplished. All associated Protection Testing and Commissioning of the new 11kV switchgear and associated 800kVA Transformer were completed post installation of cabling. New earthing matrix and earth bonding was completed, and safety critical tripping circuits were first fixed ready for phase two of the project for final connections and commissioning testing.

New HV and LV cables were installed and tested as part of the scope of work and further civil works completed to reveal the main HV incoming cable that supplied existing HV substation that was due to be disconnected and cut away off system. This work was in preparation for phase two of the project.

Phase two of the project was booked in out of hours so the existing substation could be shut down for the day whilst the rest of the works could be completed, this was all agreed with the client at planning stages.

The mains power to the existing substation was isolated locally from the client’s main intake substation. The RJ Power SAP completed all associated safety documentation and also completed cable identification testing and spiking procedures of the incoming HV cable ready for jointing. Also, existing HV apparatus and cabling was proved dead at points of work following safe working zone procedures, so existing apparatus could be disconnected and cut away off the system. The scope of works required the existing apparatus to be disconnected and made safe off system only as the client organised for the apparatus to be collected and recycled at a later date.

The LV cables from the existing transformer onsite were disconnected and removed from the clients main LV switchboard, and new LV cables from the new HV transformer were installed and connected into the existing LV switchboard. The existing HV incoming cable from main intake substation was prepared and a HV straight joint completed to provide new HV connection in to new HV substation switchgear.

The second fix of earthing matrix and earth bonding was then completed along with final connections of safety critical tripping circuits. Post installation commissioning testing was completed to test full integrity of the new HV/LV system installed. The redundant HV switchgear and HV transformer were marked up and identified as out of service and off system and made safe for the client to remove at later date.

The HV and LV system was then restored and post installation checks and testing was completed to confirm that the site network was healthy, with no issues and was in back to normal service position.

Full on site reports of the works were completed and forwarded back to the RJ Power North office for final O&M project reports to be completed and sent across to the client.

RJ Power North’s engineering delivery team consisted of: 1 x Senior Authorised Person, 1 x Protection Engineer, 1 X Electrical Fitter team (Fitter and Fitters mate) and 1 x HV Jointer team (HV Jointer and Jointers mate).


The main challenges of this projects were:


RJ Power North Limited
Unit 8 Forest Business Park
YO19 4RH
01904 238256
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