PROGRAMME DESCRIPTION:

The Thameslink project required additional load capacity from Tottenham 132kV Grid to feed the increased traction loading at Hornsey due to the introduction of new trains.

To facilitate this load requirement, Network Rail commissioned UKPNS to decommission Northumberland Park 25kV Traction Feeder Station (which was fed off Tottenham Grid) and install a new 25kV Feeder Station at Brimsdown. The new Traction Feeder Station would be fed off Brimsdown 132kV Grid

Powersys were approached by UKPNS to develop a Network Rail GRIP 1-3 Single Option Approval In Principle Form A design.

PROJECT DESCRIPTION:

In order to ensure that this complex project had a good fundamental concept design, it was initially imperative to understand the existing and proposed locations of the respective traction feeder stations and the likely connection routes which would be used. This required Powersys to undertake detailed site surveys as part of this concept works and propose multiple options for the location of the new traction feeder station.

As part of these works, coordination with OLE Engineers was required due to the nature of the existing and new connections as well as logistics teams to ensure that equipment and plant could be delivered to all the sites considered under our options.

Initially circa 10 options were proposed for the location of the new Brimsdown Traction Feeder station. For all these options, the following would have to be carried out to validate the options proposed:

• Liaison with existing landowners and businesses.
• Infrastructure surveys.
• Dilapidation survey of Northumberland Park Feeder Station.

From these liaisons, landowners were generally reluctant to provide land to cater for this facility, due to this, innovative concept designs had to be produced to made the location and associated routes more appealing to the local businesses and landowners.

Powersys developed multi-option deliverables, based on experience in engineering design and delivery.

Following approval from local land owners, we then recommended a single option solution.

The following deliverables were produced to formulate the Form A - Approval in Principle design.

• Survey report
• Dilapidation Survey report
• Site access and location assessment
• Switchgear selection assessment
• Neutral Section and OLE Assessment
• Protection and Control Report
• SCADA and Telecoms Assessment
• Civil Assessment.
• Bill of Quantities with estimated costs.
• Testing and Commissioning Plan
• Designer’s Risk Assessment
• Single Option Assessment Report

The Form A Approval in Principle submission to Network Rail included over 35 drawings and technical reports. Included as part of this deliverable was the suggestion of using Air Insulated switchgear to replace the potentially hazardous Gas Insulated Switchgear, an innovation which has subsequently been utilised across multiple NR sites.