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Sagging Calculation

The document provides parameters and calculations for sagging of an overhead conductor. It gives specifications of the conductor including diameter, cross-sectional area, weight and material properties. It then calculates the working tension, stress and sag at different temperatures ranging from minimum to maximum expected values using formulas that account for factors like expansion, span length and weight loading. The maximum and minimum sag are found to be 10.55776112 m and 7.90481106 m respectively for a 350m span conductor under given temperature conditions.

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234 views3 pages

Sagging Calculation

The document provides parameters and calculations for sagging of an overhead conductor. It gives specifications of the conductor including diameter, cross-sectional area, weight and material properties. It then calculates the working tension, stress and sag at different temperatures ranging from minimum to maximum expected values using formulas that account for factors like expansion, span length and weight loading. The maximum and minimum sag are found to be 10.55776112 m and 7.90481106 m respectively for a 350m span conductor under given temperature conditions.

Uploaded by

wiizt
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as DOCX, PDF, TXT or read online on Scribd
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PARAMETER PERHITUNGAN SAGGING

Ultimate Tensile Strength (UTS) : 8810.348 kg


Overall diameter of Conductor (d) : 21.9 mm
Area of Cross section of Conductor (A) : 243 mm2
Weight of Conductor (w) : 0.987 kg/m
Coefficient of linear Expansion (α) : 0.0000189 /°C
Young’s Modulus of elasticity (E) : 7700 kg/mm2
Maximum temperature : 80° C
Minimum temperature : 10° C
Everyday temperature : 27° C
Factor of Safety (FOS) (at 27° C) : 5
Ground clearance : 13.5 m
Weight of Conductor per unit area (δ) : 𝑤 0.987
𝛿= =
𝐴 243
= 0.004061728 𝑘𝑔⁄𝑚⁄𝑚𝑚2
Equivalent Span (L) : 350 m

Initial Condition

Temperature = 27° C
𝑈𝑇𝑆 8810.34808
Working Tension 𝑇1 = 𝐹𝑂𝑆 = 5
= 1762.069616 𝑘𝑔

𝑇1 1762.069616 𝑘𝑔⁄
Working Stress 𝑓1 = = = 7.251315292
𝐴 243 𝑚𝑚2

𝑃2 +𝑤 2
Loading Factor 𝑞1 = √ = 1 (𝑓𝑜𝑟 𝑛𝑜 𝑤𝑖𝑛𝑑; 𝑃 = 0)
𝑤

𝐿2 × 𝛿 2 × 𝑞1 2 × 𝐸
𝑓1 2 × (𝑓1 − 𝑘) =
24

𝐿2 × 𝛿 2 × 𝑞1 2 × 𝐸
𝑘 = 𝑓1 −
24 × 𝑓1 2

3502 × 0.0040617282 × 12 × 7700


𝑘 = 7.251315292 −
24 × 7.2513152922

𝑘 = −5.079839582

Maximum Temperature Condition

Temperature = 80° C

𝑃2 +𝑤 2
Loading Factor 𝑞2 = √ 𝑤
= 1 (𝑓𝑜𝑟 𝑛𝑜 𝑤𝑖𝑛𝑑; 𝑃 = 0)
Difference of Temperature 𝑡 = 80 − 27 = 53° 𝐶

The working stress is determined by the following formula:

𝐿2 × 𝛿 2 × 𝑞2 2 × 𝐸
𝑓2 2 [𝑓2 − (𝑘 − 𝛼 × 𝑡 × 𝐸)] =
24

3502 × 0.004061728 2 × 12 × 7700


𝑓2 2 [𝑓2 − (−5.079839582 − 0.0000189 × 53 × 7700)] =
24

𝑓2 2 [𝑓2 − (−12.79292958)] = 648.391526

𝑘𝑔⁄
𝑓2 = 5.890947462
𝑚𝑚2

Working Tension 𝑇2 = 𝑓2 × 𝐴 = 5.890947462 × 243 = 1431.500233 kg

𝐿2 ×𝛿×𝑞2 3502 ×0.004061728×1


Maximum Sag 𝑠 = 8×𝑓2
= 8×5.890947462
= 10.55776112 𝑚

Minimum Temperature Condition

Temperature = 10° C

𝑃2 +𝑤 2
Loading Factor 𝑞3 = √ 𝑤
= 1 (𝑓𝑜𝑟 𝑛𝑜 𝑤𝑖𝑛𝑑; 𝑃 = 0)

Difference of Temperature 𝑡 = 10 − 27 = −17° 𝐶

The working stress is determined by the following formula:

𝐿2 × 𝛿 2 × 𝑞3 2 × 𝐸
𝑓3 2 [𝑓3 − (𝑘 − 𝛼 × 𝑡 × 𝐸)] =
24

3502 × 0.004061728 2 × 12 × 7700


𝑓3 2 [𝑓3 − (−5.079839582 − 0.0000189 × (−17) × 7700)] =
24

𝑓3 2 [𝑓3 − (−2.605829582)] = 648.391526

𝑘𝑔⁄
𝑓3 = 7.868020574
𝑚𝑚2

Working Tension 𝑇3 = 𝑓3 × 𝐴 = 7.868020574 × 243 = 1911.928999 kg

𝐿2 ×𝛿×𝑞3 3502 ×0.004061728×1


Maximum Sag 𝑠 = 8×𝑓3
= 8×7.868020574
= 7.90481106 𝑚
No. Equiv. Temperature
Span 10° C 27° C 80° C
(m) Sag (m) Tension (kg) Sag (m) Tension (kg) Sag (m) Tension (kg)
1 250 3.84 2009.705 4.38 1762.069 6.05 1275.709412
2 300 5.69 1953.299 6.31 1762.069 8.15 1363.413335
3 350 7.91 1911.928 8.58 1762.069 10.57 1431.500233
4 400 10.50 1881.642 11.21 1762.069 13.31 1484.938504
5 450 13.45 1859.202 14.20 1762.069 16.39 1527.335447

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