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TLP Electrification and Signalling Interface Issues 1

Date 28-01-2014

Thameslink ProgrammeElectrification & Signalling Interface Issues

Martin Sigrist – Principal Design Engineer (E&P)

Date 28-01-2014 TLP Electrification and Signalling Interface Issues 2

Content

• Introduction

• What is Thameslink

• Outline of Electrification on Thameslink

• Dual Electrification

• Autotransformer System

• Earthing and Bonding

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What is Thameslink

• Thameslink Programme high level requirements for the route (s)

–12 car trains

–24 trains an hour (in each direction) within the Core Area

• Including up to 32 TPH in perturbation recovery

• E&P Requirements

–Electrification system capable of feeding the above

– Initial scope developed in 90’s under Thameslink 2000, but developed further under the current scheme

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What is Thameslink

Bedford

Luton

St Albans

Farringdon

Blackfriars

Elephant & Castle

London Bridge

Wimbledon SuttonE Croydon

Brighton

Streatham

St Pancras Thameslink

WimbledonSevenoaks

Cambridge

Peterborough

Bedford

Luton

St Albans

Welwyn Garden City

St Pancras ThameslinkFarringdon

Blackfriars

Elephant & Castle

London BridgeBexleyheath

SidcupDartford

Sutton

Tattenham Corner

E Croydon

Horsham

Brighton

Caterham

East Grinstead

Ashford

Final Service pattern post–KO2

Initial service pattern

Sevenoaks

KO2 service still being finalised

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Electrification on TLP

• The original system design identified a number of upgrades to both the AC and DC Systems, this mainly comprised of:

– 25kV Traction Enhancement on the MML due low volts at City Thameslink under outage (N-1)

– 750V DC System upgrades at know weak areas and for equipment overloading under outage (N-1)

– Extension of the Dual Electrified Area between Farringdon and City Thameslink, driven by operational requirements

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Dual Electrified Area

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Dual Electrified Area• Old Layout between Farringdon and Blackfriars with an 8 Car

Contactor Section

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Dual Electrified Area• New layout between Farringdon and Blackfriars with an

extended DEA and 12 Car Contactor Section

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Dual Electrified Area

• Issues arising:

–Design choice of track circuits – single or double

–Stray currents both AC and DC – effects to track circuits

–DC Stray currents – corrosion

–Track circuit reliability – new issue following commissioning was IRJ Arcing

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Dual Electrified Area• Further investigations in to old issues like revisiting

stray current on Thameslink as part of the AC/DC interface

• Testing, monitoring and analyzing to better understand the drivers of stray current in order to predict the changes as the service level changes in future timetables

• An interim monitoring system is currently in use and this will be made permanent following out investigations:

–DC Stray Current (for corrosion and immunisation –to DC track circuits)

–AC Stray Current (for immunisation – to AC track circuits)

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Resolving Issues - Examples on TLP

• IRJ Arcing?

• Not considered or known about during the initial design

• Currently being monitored and assessed

• Four solutions being investigated, including arc diverters and contactors installed closer to the IRJ

• Arc Diverter in Operation

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Resolving Issues - Examples on TLP

BeforeAfter

• What happens to IRJ arcing when cables are shorten?

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Autotransformer Upgrade on MML

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AT Upgrade on MML• The original Thameslink 2000 concept removed Regents Canal

FS at St Pancras and added AT on MML and ECML (WIP?)

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AT Upgrade on MML• Overview of the 25kV Classic fed system on the MML, with

convention bonding

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AT Upgrade on MML

Kentish Town SATS Grahame Park MPATS

BorehamwoodATFS

Sandridge Road MPTSC

Cricklewood Depot

NGC 400kVNGC 400kV

• Overview of the TLP Autotransformer Upgrade Scheme on the MML, which required enhanced bonding over the complete length

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Autotransformer Staging• The Thameslink Autotransformer installation was broken down into 7

key stages, these are:

– Stage 1 = Install Return Screen Conductor (RSC) & additional Cross Track Bonding (XTB)

– Stage 2 = Switchgear Renewal

– Stage 3 = Remove BT/RC System

– Stage 4 = 1st National Grid (NG) feed installed and commissioned

– Stage 5 = Borehamwood neutral section

– Stage 6 = Full AT System

– Stage 7 = 2nd NG feed installed and commissioned

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Basic Conversion from…..Up

SlowDown Fast

F/02/66F/02/66

B/29/FB/26/S

F/06/22F/06/22

F/08/31F/08/31

F/11/16F/11/18

F/13/19F/13/19

F/16/26F/17/04

F/16/26F/16/31

F/19/33F/20/04

F/19/36F/20/07

F/21/10BF/21/10B

Kentish TownSATS

Grahame ParkFS

BorehamwoodFS

Down Slow

Up Fast

Example of how the BT/RC system was converted to a Rail Return with RSC

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Via…..

Additional Cross Track Bonding and RSC

Removal of Booster Transformers

Each section defined between Mid-Point Connections (MPCs)

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And…..

Installation of AT Aerial Feeder

Protection System Changed

Shows route of Telecoms cable that needs to be immunised

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To……

Completed conversion from BT/RC to RSC/ATF

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AT Upgrade on MML• Issues arising:

–Track circuit reliability – Implementation of enhanced bonding causing track circuit failures and bonding failures

–AT Safety Case – effects of AT system on track circuits considered various scenarios inc AC Immunisation at Blackfriars (via the DEA) and levels on DC components of AT transformer inrush. All of these are now included in the Generic Electrification Safety Case

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AT Upgrade on MML

• Grahame Park bonding failure caused by Grid transformer failure at Borehamwood - operational issues in service reduction

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Earthing and BondingChris Wilson

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E&B Issues (1)

• Earthing and Bonding Issues in the Core Area

–Recent issues found currently being investigated

–The design of not just Electrification and Signalling disciplines needed

–Failure to understand the E&B completely could present track circuit reliability issues

• An example of the Thameslink Core Area – the Clerkenwell Tunnels

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E&B Issues (2) – TRR and RC

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E&B Issues (3) – Add EW

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E&B Issues (4) – Station Earths

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E&B Issues (5) – FSP Earthing

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E&B Issues (6) – Telecoms RSC

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E&B Issues (7) – Fire Main

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E&B Issues (8) – Cable Tray

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E&B Issues (9)

• The issue of parallel connections is not an issue just to consider for track circuit reliability.

• Earthing and Bonding

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Any Questions?