Sag Calculation [PDF]

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Temperature Wind Factor of Safety Working tension (T1)

Working Stress(f1)

Loading factor; q2 = √ P2 + w2 = 1 (for no wind; P = 0) The working stress is determined by the following formula: k = f1 – ℓ2 δ2 q12Ef/24f12

k = f1 – ℓ2 δ2 q12Ef/24f12 = 883.62

= 883.62

= 883.62

= 37.062

CONDITION: 2

Temperature = 75 Wind Loading factor; q2 = √ P2 + w2 = 1 (for no wind; P = 0) Difference of temperature; t = 75 – 32.2 = 42.8 °C The working stress is determined by the following formula: 2

f2 [f2 – (k – α t Ef) =

ℓ2 δ2 q2 Ef 24

f22 [f2 – (-147.701 – (19.3x10-6 ) x 42.8 x (0.686x106))) =

2

f22 [f2 +714.36542 ) = 6E+18 24 2

f2 [f2 +714.36542 ) = 3E+17 Work Tension (T2)= f2xa = 555.553321x4.845 = 2691.7

2 2 2 Maximum Sag ; s= ℓ δ q 8 x f2

CONDITION : III

2

2

(260) x (0.373180077) x(1) x( 24

Loading factor; q2 = √ P2 + w2 = 1 (for no wind; P = 0) Temperature = (-) 250c Wind = NIL Difference of temperature; t = 75 – 32.2 = 42.8 °C

2

f2 [f2 – (k – α t Ef) =

ℓ2 δ2 q2 Ef 24

f32 [f3 – (-147.701 – (19.3x10-6 ) x (-34.7) x (0.686x106))) =

2

2

2

(260) x (0.373180077) x(1) x( 24

8 2 f3 [f3+ 311.719083.919470757x10 )=

=

40

=

NIL

=

2

=

U.T.S = FOS

=

2306 Kg

=

=

=

kg/cm2

-

9225 4

2306.25 2.61

(260)2 X (0.373180077)2 X (1)2 X(0.686X106) (24)2 X (685.75851)2

-

6458143809 270872486.8

-

=

75

=

NIL

he following formula: ℓ2 δ2 q2 Ef 24

2

2

2

6

(260) x (0.373180077) x(1) x(0.686x10 ) 24

Kg / cm2

555.553321x4.845 kg/cm2

ℓ2 δ2 q2 Ef 24

2

2

2

6

(260) x (0.373180077) x(1) x(0.686x10 ) 24

3.919470757x108

CONDITION: I Temperature = 32.2 °C Wind = NIL Factor of Safety = 4 Working tension; T1 F.O.S. Working Stress; f1 Loading factor; q1 = √ P2 + w2 = 1 (for no wind; P = 0) k = f1 – ℓ2 δ2 q12Ef/24f12 CONDITION: II Temperature = 75 °C

Sag

CONDITION: II Temperature = 75 °C Wind = NIL Loading factor; q2 = √ P2 + w2 = 1 (for no wind; P = 0) w Difference of temperature; t = 75 – 32.2 = 42.8 °C The working stress is determined by the following formula: f2 2 [f2 – (k – α t Ef) = ℓ2 δ2 q2 2 Ef 24

75

2306.25 4 #DIV/0! 344.6396307

-251.1513693 268829691.4

7.879625

f2 2 [f2 – {– 147.70198 – (19.3 × 10 – 6) × 42.8 × (0.686 × 106)}] = (350)2 × (0.334571723)2 × (1)2 × (0.686 × 106) 24 f2 2 (f2 + 714.36542) = 3.919470757 × 108 ∴ f2 = 555.553321 Kg / cm2 Working tension; T2 = f2 × A = 555.553321 × 4.845 = 2691.656 Kg / cm2 Maximum Sag; s = ℓ2 δ q2 8 × f2 = (350)2 × (0.334571723) × (1) 8 × 555.553321 = 9.22 metres

Sag Calculations for 33KV OH

Sag calculations for 33 KV OH LINE - SRIRENGARAJ ISPAT PARAMETERS:

Value

Basic Span (ℓ) : Ultimate Tensile Strength of Conductor (U.T.S.) : Overall diameter of the Conductor (d) Weight of the Conductor (w) Wind Pressure (P) : Coefficient of linear Expansion (α) Young’s Modulus of elasticity (Final) (Ef) : Young’s Modulus of elasticity (Initial) (Ei) : Maximum temperature (Ambient) Maximum temperature (Conductor) : Minimum Temperature (Ambient) : Minimum Temperature (Conductor) : Every day Temperature : Area of Cross section of Conductor (A) : Factor of Safety (F.O.S.) Factor of Safety (F.O.S.) (Otherwise) : Weight of Conductor per unit area (δ) :

UOM

260 9225 21 0.974 83.38 19.3 X10-6 0.686 × 10 6 0.4675 × 10 6 50 75 -2.5 -2.5 40 2.61 4 2 0.373180077

Minimum Ground Clearance : 7.01 metres

mtrs kg mm kg/m kg/m2 per Deg cel Kg / cm2 Kg / cm2

6

CONDITION :1 Temperature = 32.2 °C Wind = NIL Factor of Saftey = 4 Working tension ; T1 =

U.T.S FOS

=

9225 4

T1=

Working Stress ; f1 =

2306.25

Kg

T1 A

=

f1=

2306.25 2.61 883.6206897

Loading factor; q2 = √ P2 + w2 = 1 (for no wind; P = 0) The working stress is determined by the following formula:

Kg/cm2

f1

k=

=

=

=

k=

883.6206897

883.6206897

883.6206897 538.9814554

CONDITION :II Temperature = 75 °C Wind = NIL Factor of Saftey = 4 Loading factor; q2 = √ P2 + w2 = 1 (for no wind; P = 0)

Difference of Temperature ;t= 75--40 = 35 The working stress is determined by the following formula:

f22 [f2 – (k – α t Ef)

=

f22 [f2 – (538.9814554 – 19.3 X10-6x35 x0.686 × 10 6)

=

f22 [f2+

525.741655 )

=

f22 [f2+

525.7416554 )

=

f2

=

Working tension ; T1 =

U.T.S

x

= =

Maximum Sag ; s=

ℓ2 δ2 q2 8 x f2

=

(260)2X (0.373180077)2 X (1) 8X(f2)

=

#DIV/0!

CONDITION :II Temperature = -2.5 °C Wind = NIL Factor of Saftey = 4 Loading factor; q2 = √ P2 + w2 = 1 (for no wind; P = 0)

Difference of Temperature ;t= 75--40 = 883.6206897 The working stress is determined by the following formula:

f22 [f2 – (k – α t Ef)

=

f22 [f2 – (538.9814554 – 19.3 X10-6x35 x0.686 × 10 6)

=

f22 [f2+

#REF!

)

=

f22 [f2+

#REF!

)

=

Working tension ; T1 =

f2

=

U.T.S

x

= =

Maximum Sag ; s=

ℓ2 δ2 q2 8 x f2

=

(260)2X (0.373180077)2 X (1) 8X(f2)

=

#VALUE!

Sag Calculations for 33KV OH LINE -SRIRENGARAJ ISPAT

133 50 20 70 273

ℓ2 δ2 q12Ef 24f12 (260)2 x (0.373180077)2x(1)2 x (0.686x106) 2

(24) x (883.6206)

6458143796 18738852.56

344.6392343

ℓ2 δ2 q22Ef 24 (260)2 x (0.373180077)2x(1)2 x (0.686x106) 24

6458143796 24

269089324.8

kg/cm2

A

(260)2X (0.373180077)2 X (1) 8X(f2)

#DIV/0!

metres

ℓ2 δ2 q22Ef 24 (260)2 x (0.373180077)2x(1)2 x (0.686x106) 24

#VALUE! 24

#VALUE!

2

kg/cm

A

(260)2X (0.373180077)2 X (1) 8X(f2)

#VALUE!

metres