Electric Power Generation, Transmission, and Distribution

1000 and 300 ft. Typical tension constraints of 15% final unloaded at 60 8 F, 25% initial unloaded at 60 8 F,

and 60% initial at maximum loading are used.

With most sag-tension calculation methods, final sags are calculated for both heavy ice=wind load and

for creep elongation. The final sag-tension values reported to the user are those with the greatest increase

in sag.

14.3.2.1 Initial vs. Final Sags and Tensions

Rather than calculate the line sag as a function of time, most sag-tension calculations are determined

based on initial and final loading conditions. Initial sags and tensions are simply the sags and tensions at

the time the line is built. Final sags and tensions are calculated if (1) the specified ice and wind loading

has occurred, and (2) the conductor has experienced 10 years of creep elongation at a conductor

temperature of 60 8 F at the user-specified initial tension.

TABLE 14.5 Tension Differences in Adjacent Dead-End Spans

Conductor: Drake

795 kcmil-26=7 ACSR Span¼700 ft

Area¼0.7264 in.^2

Creepisa factor NESC Heavy Loading District

Resultant

Weight, lb=ft

Final Initial

Temp, 8 F Ice, in.

Wind,

lb=ft^2 K, lb=ft Sag, ft Tension, lb Sag, ft Tension, lb

0 0.50 4.00 0.30 2.509 13.61 11318 13.55 11361

32 0.50 0.00 0.00 2.094 13.93 9224 13.33 9643

 20 0.00 0.00 0.00 1.094 8.22 8161 7.60 8824

0 0.00 0.00 0.00 1.094 9.19 7301 8.26 8115

30 0.00 0.00 0.00 1.094 10.75 6242 9.39 7142

60 0.00 0.00 0.00 1.094 12.36 5429 10.65 6300 a

90 0.00 0.00 0.00 1.094 13.96 4809 11.99 5596

120 0.00 0.00 0.00 1.094 15.52 4330 13.37 5020

167 0.00 0.00 0.00 1.094 16.97 3960 15.53 4326

212 0.00 0.00 0.00 1.094 18.04 3728 17.52 3837

aDesign condition.

Conductor: Drake
795 kcmil-26=7 ACSR Span¼1000 ft
Area¼0.7264 in.^2
Creep isnota factor NESC Heavy Loading District

Resultant

Weight, lb=ft

Final Initial

Temp, 8 F Ice, in.

Wind,

lb=ft^2 K, lb=ft Sag, ft Tension, lb Sag, ft Tension, lb

0 0.50 4.00 0.30 2.509 25.98 12116 25.98 12116

32 0.50 0.00 0.00 2.094 26.30 9990 25.53 10290

 20 0.00 0.00 0.00 1.094 18.72 7318 17.25 7940

0 0.00 0.00 0.00 1.094 20.09 6821 18.34 7469

30 0.00 0.00 0.00 1.094 22.13 6197 20.04 6840

60 0.00 0.00 0.00 1.094 24.11 5689 21.76 6300 a

90 0.00 0.00 0.00 1.094 26.04 5271 23.49 5839

120 0.00 0.00 0.00 1.094 27.89 4923 25.20 5444

167 0.00 0.00 0.00 1.094 30.14 4559 27.82 4935

212 0.00 0.00 0.00 1.094 31.47 4369 30.24 4544

aDesign condition.