Rocky Mountain Power 2011 Clinic Dynamic Line Rating System Zhao Qi University of Utah

2 Outline Background Proposed solution Actual Design Problems Budget Timeline

3 Background All-Inclusive Measurement line 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 T r – Resultant conductor tension T h – 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 QtyDescriptionCostTotal 1Transformer$0 2Cable$0 2Transformer Pad$20$40 4Various lugs, clamps, connectors $20$80 1Circuit breaker$300 3Locking plug$42$126 1Tension meter$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 References: [1]- “Overhead Conductor Manual”, 2 nd 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, [online]. Available: