SWEDE - April 27 th, 2012 - Galveston Tommy Nylec Austin Energy Spacer Cable Application

SWEDE - April 27th, 2012 - GalvestonTommy Nylec

Austin EnergyAustin EnergySpacer Cable ApplicationSpacer Cable Application

Austin EnergyAustin EnergySpacer Cable ApplicationSpacer Cable Application

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OverviewOverviewOverviewOverview

Introduction to Austin Energy

Spacer Cable Description

Applications Operational Concerns

Future Work and Conclusions

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Austin Energy StatisticsAustin Energy StatisticsAustin Energy StatisticsAustin Energy Statistics

>400,000 Customers >2,800 MW Generation > 50 Distribution

Substations > 10,000 miles of

Distribution >1,600 Employees Serve 437 square miles

including Austin city limits and neighboring areas

Started in 1887

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Austin Energy’s Operational ViewAustin Energy’s Operational ViewAustin Energy’s Operational ViewAustin Energy’s Operational View

City Council is Board of Directors

Citizens equivalent to Investors/Members

Public Opinion drives utility direction

Alternative Energy Initiative

Integrate nature into city

Goal to become compact city

City ordinances

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Spacer Cable IntroductionSpacer Cable IntroductionSpacer Cable IntroductionSpacer Cable Introduction

Spacer cable is a messenger supported primary distribution system using covered conductors in a close triangular configuration. The system has the mechanical strength to weather severe storms and the electrical strength to prevent faults due to phase to ground or phase to phase contact, tree contact or animal contact.

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Cable DetailsCable DetailsCable DetailsCable Details

Messenger Supports conductors and maintains phase spacing Messenger supports the spacers and conductors and

may be used as system neutral. Messengers up to 4/0 AWG equivalent conductivity

are available Shields system from lightning strikes Special messengers available for long spans Conductor Available in various voltages & sizes High density polyethylene (gray or black) UV resistant Track resistant Long leakage distance, self-washing design allows

operation with contamination

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Spacer DetailsSpacer DetailsSpacer DetailsSpacer Details

Voltage

Dimensions (in)

Conductor Spacing (in)

Messenger Range (in)

Cable Range (in)Max System

Voltage (kV)

Short Circuit Rating

(kA)Weight (lbs)

D E AN AC BC

15 kV 16.5 23.5 8.5 8 8 10.75 .375-.750 .438-2.00 13.5 2.5

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Bracket DetailsBracket DetailsBracket DetailsBracket Details

Voltage

Dimensions (in)

Minimum Ultimate Load (lbs) V1 (vertical)Weight

(lbs)A B

15 kV 8 14 3200 8.6

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Spacer Cable ApplicationSpacer Cable ApplicationSpacer Cable ApplicationSpacer Cable Application

Heavily wooded or trimming limitations ROW or property line boundaries

Clearance concerns Under built facilities

Multiple circuits Critical reliability

Sensitive environmental areas Long span distances

Public request for fewer poles

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Designing with Spacer CableDesigning with Spacer CableDesigning with Spacer CableDesigning with Spacer Cable

Pole loading can be reduced Conceptually similar to overhead fiber

design Requires unique sag and tension tables Technical design guides available PLS-CADD data for modeling purposes Turnkey services available from vendors

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Spacer Cable InstallationSpacer Cable InstallationSpacer Cable InstallationSpacer Cable Installation

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Tangent FramingTangent FramingTangent FramingTangent Framing

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Dead End FramingDead End FramingDead End FramingDead End Framing

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Angle FramingAngle FramingAngle FramingAngle Framing

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Tap ConnectionsTap ConnectionsTap ConnectionsTap Connections

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Installation ExamplesInstallation ExamplesInstallation ExamplesInstallation Examples

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River Crossing ExampleRiver Crossing ExampleRiver Crossing ExampleRiver Crossing Example

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River Crossing ExampleRiver Crossing ExampleRiver Crossing ExampleRiver Crossing Example

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Dead End Framing ExampleDead End Framing ExampleDead End Framing ExampleDead End Framing Example

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Tree Trimming ImpactTree Trimming ImpactTree Trimming ImpactTree Trimming Impact

Reduces vegetation management costs due to extending cycles through smaller footprints

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Spacer Cable Operational ObservationsSpacer Cable Operational ObservationsSpacer Cable Operational ObservationsSpacer Cable Operational Observations

Prevents faults caused by incidental contact

Requires special tools and techniques Very difficult to remove covering Allows taps without additional hazards

sometimes created by vertical construction

Treat as uninsulated when being worked

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Spacer Cable Technical BenefitsSpacer Cable Technical BenefitsSpacer Cable Technical BenefitsSpacer Cable Technical Benefits

Designed to prevent storm related outages

Compact design High mechanical

strength Lightning shield wire Less voltage drop

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Initial Cost versus O&M SavingsInitial Cost versus O&M SavingsInitial Cost versus O&M SavingsInitial Cost versus O&M Savings

+Material more expensive than standard construction

+Can be more labor intensive until familiar with equipment

- Reduction of tree trimming expenses

- ROW acquisition costs reduced

- Messenger use requires less structurally significant poles

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Spacer Cable at Austin EnergySpacer Cable at Austin EnergySpacer Cable at Austin EnergySpacer Cable at Austin Energy

Initially used for long spans for river crossings and long highway crossings

Still primary use Beginning to investigate use for zero lot

line & tree trimming reduction 795 only option w/ 4/0 equivalent

neutral

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SummarySummarySummarySummary

Advantages Great for long spans Can reduce tree trimming Can use shorter poles Great for multiple circuits or existing ROW Very reliable

Disadvantages Higher initial costs versus standard overhead lines Pole breaks before messenger Difficulty during install or reinstall Not always supported by line workers

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Questions?Questions?Questions?Questions?

Additional technical information can be found at http://www.pesicc.org