Rocky Mountain Power 2011 ClinicDynamic Line Rating System

Zhao QiUniversity of Utah

2

Outline

• Background• Proposed solution• Actual Design Problems• Budget• Timeline

3

Background

• All-Inclusive Measurementline temperature, environment temperature, Solar Absorption

• Accuracy• Low-Power Draw

4

•

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 Calculations

Fig. 1

5

Ice and Wind Loading

• Radial Ice

• Wind Pressure

• Wind & Ice Combined

6

Ice and Wind Loading

Table. 1 Definitions of Ice and Wind Load for NESC Loading Areas

7

Ice and Wind Loading

Fig. 2 Ice and Wind Load Areas of the United States

8

Ice and Wind Loading

• Ice loading

• Wind loading

For structures below 60 feet:

For structures exceed 60 feet:

• Resultant ice and wind loading

9

Actual Design Conditions

• The length of conductors DO NOT remain constant

a) High temperature

b) Stretching because of tension

• Vibration of conductors due to wind

a) Wind speed

b) Pole height

c) Span length

d) Tension

10

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

11

Timeline

12

Conclusion

• Background / proposed solution• Actual Design Problems

- Ice and wind loading- length of conductor- Aeolian vibration

• Budget• Timeline

13

Questions?

Contact information:

Zhao Qi

ECE department, University of Utah

u0589543@utah.edu

References:

[1]- “Overhead Conductor Manual”, 2nd Edition, Southwire Company, 2007

[2]- IEEE “Guide to the Installation of Overhead Transmission Line Conductor”, 2004

[3]- IEEE “Guide on Conductor Self-Damping Measurements”, 1978

[4]- “Sag and Tension”, Sep. 20, 2011. [online]. Available:

http://www.iaei.org/magazine/2004/05/the-effects-of-ruling-span-on-sag-and-tension/