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
