OCS Design in Regions of EMI:

University Link and Northgate Link

Anya Grechka, PE

January 27, 2014

Overview

• Link Light Rail Extensionso Overviewo EMI Region

• EMI Introductiono Testingo Changes in Magnetic Field

• OCS Design for EMIo Methodologyo Drawings

• Further Considerations

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Link Light Rail ExtensionsOverview

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Link Light Rail ExtensionsEMI Region

4“Source: https://maps.google.com/

EMI Introduction

• Earth’s magnetic field• Electromagnetic field

• B-field generation• Effects on lab equipment

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Source: http://gaussbusters.com/resources/articles/principles-of-magnetism/

EMI IntroductionTesting

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EMI IntroductionChanges in Magnetic Field

1. Current flowing for propulsion• Distance between dipole

sources • Distance from source

2. Movement of ferrous materials through Earth’s magnetic field causing perturbation

• Shielding• Active cancellation

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Source: “Magnetic Field of Electrified Railway Line I Slovenia” by Bojan Cene

OCS Design for EMIMethodology

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• SCFT system in tunnels• Standard Sound Transit conductor sizes• MW only for mechanical support, no current • Feeder cable connected in parallel with CW• Riser cables at regular intervals• Optimized ratios to minimize B-field:

OCS Design for EMIAssembly Drawings

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OCS Design for EMIAssembly Drawings

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OCS Design for EMIGeneral Arrangement

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Further Considerations

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• Wear of the CW• Material of MW• Resistance of clamps and risers• Installation tolerances• Crossover design

Contact: agrechka@ltk.com

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Thank You!