Rocky Mountain Power 2011 Clinic Project Dynamic Line Rating Preliminary Design Review Project Advisor: Dr. Thomas Schmid Clinic Team Members: Skyler Kershner,

Rocky Mountain Power 2011 Clinic Project

Dynamic Line RatingPreliminary Design Review

Project Advisor: Dr. Thomas SchmidClinic Team Members: Skyler Kershner, Benjamin Sondelski, Trevor Nichols, Shayan Barzagari, Zhao Qi

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Presentation Overview

• Project Background

• Goals

• Proposed Solution

• Additional Considerations

• System Implementation

• Model

• Expected Results

• Budget / Timeline

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Project Background

• Overhead Conductor Sag

• National Electrical Safety Code specifies minimum clearance

• As conductor heats, sag increases

• Environmental, power considerations

• Dynamic line rating system needed

[1] Clearance Levels

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Project Goals

• Develop dynamic line rating system

– Combine best characteristics of commercially available models

– Simple design

• Implement system in a model

• Validate collected data

[2] Line Sag Illustration

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Proposed Method: Thermal Imaging

• Directly measures sag and line temperature

• Non-contact measurement

[4] Configuration

[5] Camera View

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Proposed Method: Thermal Imaging

• Provides high contrast images, temperature measurement

• Image processing tracks lowest point in line

[6] Thermal Image

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Proposed Method: Thermal Imaging

• Limitation: Cost

Model Price

FLIR T620 $19,500

FLIR SC325 $13,500

FLIR E60 $7,500

[7]

[8]

[9]

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Conclusion

• Need for dynamic line rating

• Goals

• Thermal imaging as potential solution

• Limitations of thermal imaging

–Other methods needed

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Overview

• Sag – Tension rating and calculation

• Tension as a solution

• Tension as a problem

• Design Problems/Solutions**

• Conclusion

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Tension as a Possible Solution

• All-Inclusive Measurement–line temperature, environment temperature, solar

absorption

• Accuracy

• Simplicity

• Low-Power Draw

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•

D – Vertical sag

S – Horizontal length of the span

W – Unit weight of the conductor

Tr – Resultant conductor tension

Th – Horizontal component of tension

Fig. 1 Parabolic Sag Curve

Sag-Tension Rating and Calculations

[10]

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Tension as a Possible Problem

• Cost

• Actual implementation– Required line outage for installation

• Ice and wind loading

• Length of Conductor–Stretching and high temperatures

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Design Problems/Solutions

• Ice loading

• Wind loading

For structures below 60 feet:

For structures exceed 60 feet:

• Resultant ice and wind loading

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Conclusion

• Overview of Tension

• Tension pros

• Tension cons

• Solutions to tension cons

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Overview

• Magnetic Field Sensing

• Implementation difficulties

• Build a model - advantages

• Conclusion

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Magnetic Field Sensor

Three Axis Magnetic Field Sensor

MAGNETOMETER RS232 W/CASE

• High Accuracy, <0.5% Full Scale• 10 to 154 Sample/Sec• Low Power consumption• Input voltage range 6 to 15 (VDC)

[11]

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Magnetic Field Measurement Difficulties

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Build a Model

• Test wide range of aspects

• Control experiment variables and environment

• Develop realistically implementable solutions

• Retain a low budget

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Conclusion

• Magnetic Sensing

• Magnetic Difficulties

• Advantages of Model

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Overview

• Proposed Solution

• Math defining model requirements

• Measuring Temperature

• Conclusion

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Proposed Solution

• Mock thermal imaging system

[12] [13]

• Build a model scaled down to 1:30 ratioApproximately 600 feet scaled to 20 feet

• Measure sag in a controlled environmentClinic Lab – Merrill Engineering Building 2350

• Develop an effective dynamic line rating system

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Math defining model

• Tension in the line – direct effect of line temperature

• Temperature – direct effect of amount of line current

• Amperage – controlled system input

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MEASURING TEMPRATURE

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MEASURING TEMPRATURE

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Conclusion

• Proposed Solution

• Characteristics of model

• Mock thermal imaging–IR thermometer–IR video camera

Physical Model: Introduction

• benefits of in-house scale model

• power supply

• electrical diagram

• conductor span

• expected model performance

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Benefits of In-House Scale Model

• communications

• controlled environment–simple comparison to IEEE

738–no exposure to weather

• verification of thermal time constant

• test bed for future clinics

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Power Supply

• need 480V, 3 phase

• 208V 3 phase is available

• 2kVA each

• power supply losses

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Model Electrical Diagram

National Electrical Code:

• bonding and grounding

• conductor sizing

• overcurrent protection

• ground detector

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Conductor Span

• 1½″ PVC structure (FORMUFIT connectors)

• transparent covering (acrylic or polycarbonate)

• dead-end attachments

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Expected Model Performance

• 20′ span

• 200lbs tension at 25°C

• Sparrow ACSR

Physical Model: Conclusion

• benefits of in-house scale model

• power supply

• electrical diagram

• conductor span

• expected model performance

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Budget

Qty Description Cost Total

1 Transformer $0 $0

2 Cable $0 $0

2 Transformer Pad $20 $40

4 Various lugs, clamps, connectors

$20 $80

1 Circuit breaker $300 $300

3 Locking plug $42 $126

1 Tension meter $1000 $1000

Total: $1566

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Timeline

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CONCLUSION

• Measure Sag

• Build a Model

• Desirable:

• Measure Conductor Temperature

• Due to budget, use Temp Sensor and IR

Camera

• Validate Measurement

• Measuring Tension

• Magnetic Sensor

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Contact Info / References

References[1] “Clearance Levels”, Oct. 3, 2011. [Online]. Available: http://www.pge.com/mybusiness/customerservice/otherrequests/treetrimming/faq/orchard/index.shtml.

[2] “Line Sag Illustration”, Oct. 3, 2011. [Online]. Available: http://redefinescience.blogspot.com/2011/05/power-lines.html.

[3] “Tension Illustration”, Oct. 3, 2011. [Online]. Available: http://www.ehow.com/how_8049821_calculate-transmission-line-tension.html.

[4] “Configuration”, Oct. 3, 2011. [Online]. Available: http://www.eng-tips.com/viewthread.cfm?qid=139418&page=274.

[5] ”Power Line View”, Oct. 3, 2011. [Online]. Available: http://forcechange.com/2190/proposed-legislation-would-speed-up-permitting-process-for-transmission-lines.

[6] “Thermal Image”, Oct. 3, 2011. [Online]. Available: http://www.x20.org/thermal/.

[7] “FLIR T620”, Oct. 3, 2011. [Online]. Available: http://www.flir.com/thermography/americas/us/content/?id=18118.

[8] “FLIR SC325”, Oct. 3, 2011. [Online]. Available: http://www.flir.com/thermography/americas/us/content/?id=31095.

[9] “FLIR E60”, Oct. 3, 2011. [Online]. Available: http://www.flir.com/thermography/americas/us/content/?id=36820.

[10] “Sag and Tension”, Sep. 20, 2011. [Online]. Available: http://www.iaei.org/magazine/2004/05/the-effects-of-ruling-span-on-sag-and-tension/

[11] “Smart Digital Magnetometer HMR2300”, Sep. 30, 2011. [Online]. Available: http://www51.honeywell.com/aero/common/documents/myaerospacecatalog-documents/Missiles-Munitions/HMR2300.pdf.

[12] “IR Thermo Gun”, Sep. 29, 2011. [Online]. Available: http://chaermai.en.ecplaza.net/2.asp.

[13] “IR Security Camera”, Sep. 29, 2011. [Online]. Available: http://www.buy.com/retail/product.asp?sku=224174617&listingid=157870950&&

Rocky Mountain Power Clinic TeamUniversity of UtahElectrical and Computer Engineering [email protected]