Q. Design the transmission line of power 110Mw and length of100km.

Economical voltage level

Veco = 5.5*(

+

Nc Veconomical (KV) Veco (KV)

1 √

Veco1 =158.87 ≈ 132

2 √

Veco2 = 116.47 ≈ 132

Iteration for calculating mf limit

Length(km) mf limit 80 2.75

100 X(let)

160 2.25

By interpolation,

(160-80)/(100-80)=(2.25-2.75)/(x-2.75)

On solving x =2.625≈ 2.63

Nc SIL cal (

Mfcal

1 =

= 43.56 =

= 2.53

2 =

= 87.12 =

= 2.262

since mf cal1 and mf cal2 are less than mf lim

i.e. ( 2.53 & 2.262 ) < 2.63 and voltage levels are same so Nc =1 .i.e. we design for single circuit

Calculation of no of disks

1. Maximum Continuous system voltage

a) 1min dry Flash Over Voltage (FOV) = 1min equivalent dry withstand voltage*FWR*NAC*FS

= 265*1.15*1.1*1.2 = 402.27Kv

So from table no. of disk = NC1 = 7

b) 1min wet FOV = 1min equivalent wet withstand voltage*FWR*NAC*FS

= 230*1.15*1.1*1.2= 349.14kv

So, NC2 = 9

2. Temporary Over Voltage

Equivalent FOV(phase voltage)= E.F.*line-line maximum system voltage *√ * FWR* NAC* FS

= 0.8 *145 *√ * 1.15 *1.1 *1.2 = 249.02 Kv

So from table, NC3= 6

3. lightning overvoltage

Equivalent FOV= BIL*FWR*NAC*FS

=550*1.15*1.1*1.2=834.6Kv

So from table, NC4 = 9

4. siwtching over voltage

Equivalent FOV = SSR*maximum sys voltage*√

*SIR* FWR*NAC*FS

= 2.75* 145 * √

1.2*1.15*1.1*1.2 = 593.07Kv

So from table, NC5 = 6

Since, greatest no Of disk is NC4 = 9,we select no of disk equals to 9.

## Note: Flash Withstand Ratio (FWR) = 1.15

Normal Atmospheric Condition (NAC)= 1.1

Factor of Safety (FS) = 1.2

Earthing Factor (EF) = 80 %

Basic Insulation Label (BIL) = 550

Switching to impulse ratio (SIL) = 1.2

Switching Surge Resistance (SSR) = 2.75

Tower Parmeters

a=

√ +FS inch ;Fs is factor of safety =9 inch

=

√ +9

=63.49 Inch

Now, l= √ *a ; l is length of string

= √ *63.49=89.78 inch

Cl= a(1 + tanθ)=2 a ; CL=Cross arm length

= 2*63.49 =126.98 inch ;θ= 45°

b=1.5a=95.235 inch

no. of ground wire used =2

y=

√

= 160.76 inch

d=√ CL-l =164.18 inch ; d is distance form gnd wire to first circuit

d’ = d +l = 253.93 inch ; d’ is distance form gnd wire to first string

Conductor Selection

Now, IL =

√

=

√ = 506.44 A

From table we choose PANTHER Conductor.

For PANTHER, R20 = 0.1375 /Km

α20 = 0.004 (linear coeff. Per°C ) for aluminum

R65 = R20(1+ α(θ65 - θ20 ) )

= 0.1375(1+.004*(65-20)) = 0.16225 /km

Transmission efficiency criterion

Power loss (Pl)= I2*R65*L

= 506.442*0.16225*100 = 4.1614 Mw/conductor

η = 1 -

; n is the no. of conductor

= 1 -

= 0.08865 (<94%)

Since, η is less go to higher conductor. On doing so for ELK,

R20 = 0.0611,R65 = 0.072098𝛀/km

Power loss = 1.8491Mw/conductor

η= 0.9445(≥94%)

So we select ELK as our design 1st conductor.

But for economical design we need to calculate our calculation for five conductors in our table we only

had one conductor available. So, we designed for bundle conductor but in single circuit bundle

conductor seems inappropriate . So we chose no. of circuit equals to two instead of one.

Then IL=

√ =

√

= 253.22A

From table we choose PANTHER Conductor.

For PANTHER,R20 = 0.1375 /Km

α20 = 0.004

R65=R20 (1 + α (θ65 - θ20 ))

= 0.1375(1+.004*(65-20)) = 0.16225 /km

Transmission efficiency critrerion

Power loss = I2*R65*L

= 253.222*0.16225*100 = 1.04 Mw/conductor

η = 1-

= 0.9432 (≥94%)

so we select PANTHER as our 1st This conductor has 37 strand,30 Al and &7 steel

Diameter of PANTHER (d) =21mm

GMRi = 0.768*d/2 = 0.768*21/2=8.064mm

GMRc=d/2 =10.5mm

GMD=√

Dab=√

Dab=√

=6.3084m

Dbc=√

6.3084m

Dca=√ =8.5027m

So GMD=6.968 m

Resistance of whole conductor (R) = 0.16225*100=16.225𝛀

Inductance of whole length (L)=.2*ln(

)

=.2*ln(

)

=1.3523mH/km= 0.135233 H

Capacitance of whole length (C) =

=8.85575*10^-12 F/m

= 8.85575*10^-7F

Z=R+jXl =16.225+ j*2*3.14*50*.13523

=45.456<69.17°

Y=jXc =j*2*3.14*50*8. 85575*10^-7 = 2.687*10^-4<90⁰

Assuming 𝛑 model

A=D=(1+

) j < ⁰

B=Z=45.456<69.17°

C=Y(1+

) = 2.6793*10^-4<90.062:

Vs= A*Vr + B*Ir

=0 < ⁰* 3 √3+45.456<69.17°*253.22<-18.195:

=83.533<6.251:KV

VR =

= (83.533*√3-132)/132 ; Vr is the voltage regulation

=9.608% ( < 12 % ) so PANTHER conductor can be used .

Corrona inception voltage criterion

Vci(line)=√ *21.1*GMRc*m*δ* (

) ; m=0.9 (factor of roughness)

√3*21.1*1.05*0.9*0.95*

; δ =0.95 is relative density of air

=213.18KV

Since Vci > (132*1.1)= 145.2 kv,corona does not occur

Tension Calculation for Different Conductors with Different Span in Different Condition

Four different conductors below the PANTHER in ASCR conductor table is chosen. Hence

Tension calculation will be done for conductor ‘ LION, BEAR, GOAT,SHEEP’ with span length of

250m ,275m, 300m, 325m 350m. Tension for Toughest, Stringing and Easiest condition are

calculated and tabulated below. Sample calculation is done for PANTHER conductor

Calculation of T2&T3

Area of conductor (A) = 261.6 mm2

Linear expansion coefficient (α) = 17.73 * per °C

Modulus of elasticity (E) =0.787 * kg/cm2 = =787000Kg/cm^2

Tension at toughest condition (T1) =

= = 4563.5 kg

Ww=100*1000*21*10^-3*2/3 = 1400kg ;Ww is weight due to wind force

Wc=976 kg/km ; Wc is weight of conductor

Wind Pressure = 100 Kg/m2

Weight of ice (Wice) = 0 kg

Weight for toughest condition (W1) = √

= √ =1706.62Kg

Wt. for the stringing , and easiest condition (W2) = Wc =976 kg /km

Then, the tension at stringing (T2) and the easiest condition (T3) is calculated using the following equation

T22[T2 +K1] –K2 =0

Where, K1=[-T1 + α(θ2-θ1)AE +

AE ]

K1=-4563.5+17.773* *27*2.616* *787000+

= -2828.11

K2 =

AE

=

=5.1071*

Using the stringing equation, the value of T2 is found to be

SO,T2 =3297.73549 kg

Similarly , T3 is calculated by

T32[T2 +K1’] –K2 ‘=0

Now, k1’=-3297.73549+ 17.773* *(67-27)*2.616* *787000+

= -657.26

K2’=k2=5.1071*

Using the stringing equation, the value of T2 is found to be

So,T3= 1971.3866 kg

For PANTHER

Diameter=21mm

area E α θ1 θ2 uts t1 Ww W1 L W2 K1 K2 t22.616 787000 1.773E-05 0 27 9127 4563.5 1400 1706.62 0.25 976 -2828.1126 5107176688 3297.73549

2.616 787000 1.773E-05 0 27 9127 4563.5 1400 1706.62 0.28 976 -2670.6498 6179683792 3254.19953

2.616 787000 1.773E-05 0 27 9127 4563.5 1400 1706.62 0.3 976 -2498.1905 7354334431 3211.32885

2.616 787000 1.773E-05 0 27 9127 4563.5 1400 1706.62 0.33 976 -2310.7347 8631128603 3169.77137

2.616 787000 1.773E-05 0 27 9127 4563.5 1400 1706.62 0.35 976 -2108.2825 10010066308 3130.02481

area E α θ1 θ2 uts t1 Ww W1 L W2 K1 K2 t32.616 787000 1.773E-05 27 60 9127 3297.735 1400 1706.62 0.25 976 -657.25993 5107176688 1971.38667

2.616 787000 1.773E-05 27 60 9127 3254.2 1400 1706.62 0.28 976 -265.38646 6179683792 1927.94504

2.616 787000 1.773E-05 27 60 9127 3211.329 1400 1706.62 0.3 976 173.708357 7354334431 1888.46548

2.616 787000 1.773E-05 27 60 9127 3169.771 1400 1706.62 0.33 976 661.357631 8631128603 1852.82806

2.616 787000 1.773E-05 27 60 9127 3130.025 1400 1706.62 0.35 976 1198.58602 10010066308 1820.79006

For LION

Diameter=22.26mm

area E α θ1 θ2 uts t1 Ww W1 L W2 K1 K2 t22.939 787000 0.00001773 0 27 10210 5105 1466.66667 1831.53517 0.25 1097 -3222.425 7248636961 3740.5042

2.939 787000 0.00001773 0 27 10210 5105 1466.66667 1831.53517 0.28 1097 -3059.607 8770850723 3700.2103

2.939 787000 0.00001773 0 27 10210 5105 1466.66667 1831.53517 0.3 1097 -2881.283 10438037224 3660.3488

2.939 787000 0.00001773 0 27 10210 5105 1466.66667 1831.53517 0.33 1097 -2687.453 12250196465 3621.4962

2.939 787000 0.00001773 0 27 10210 5105 1466.66667 1831.53517 0.35 1097 -2478.116 14207328444 3584.1052

area E α θ1 θ2 uts t1 Ww W1 L W2 K1 K2 t32.939 787000 0.00001773 27 60 10210 3740.504 1466.66667 1831.53517 0.25 1097 -943.0417 7248636961 2306.0793

2.939 787000 0.00001773 27 60 10210 3700.21 1466.66667 1831.53517 0.28 1097 -561.2109 8770850723 2267.3346

2.939 787000 0.00001773 27 60 10210 3660.349 1466.66667 1831.53517 0.3 1097 -135.383 10438037224 2231.516

2.939 787000 0.00001773 27 60 10210 3621.496 1466.66667 1831.53517 0.33 1097 335.47288 12250196465 2198.6556

2.939 787000 0.00001773 27 60 10210 3584.105 1466.66667 1831.53517 0.35 1097 852.16598 14207328444 2168.6669

For BEAR conductor

Diameter=23.45mm

area E α θ1 θ2 uts t1 Ww W1 L W2 K1 K2 t23.261 787000 1.773E-05 0 27 11310 5655 1563.33 1982.413 0.25 1219 -3605.1059 9931199771 4174.89137

3.261 787000 1.773E-05 0 27 11310 5655 1563.33 1982.413 0.275 1219 -3432.6267 1.2017E+10 4135.3237

3.261 787000 1.773E-05 0 27 11310 5655 1563.33 1982.413 0.3 1219 -3243.721 1.4301E+10 4096.08664

3.261 787000 1.773E-05 0 27 11310 5655 1563.33 1982.413 0.325 1219 -3038.3886 1.6784E+10 4057.73388

3.261 787000 1.773E-05 0 27 11310 5655 1563.33 1982.413 0.35 1219 -2816.6297 1.9465E+10 4020.70452

area E α θ1 θ2 uts t1 Ww W1 L W2 K1 K2 t33.261 787000 1.773E-05 27 60 11310 4174.8914 1563.33 1982.413 0.25 1219 -1166.3853 9931199771 2616.75004

3.261 787000 1.773E-05 27 60 11310 4135.3237 1563.33 1982.413 0.275 1219 -775.30298 1.2017E+10 2580.24836

3.261 787000 1.773E-05 27 60 11310 4096.0866 1563.33 1982.413 0.3 1219 -340.23304 1.4301E+10 2546.16316

3.261 787000 1.773E-05 27 60 11310 4057.7388 1563.33 1982.413 0.325 1219 139.723717 1.6784E+10 2514.59354

3.261 787000 1.773E-05 27 60 11310 4020.7045 1563.33 1982.413 0.35 1219 665.32383 1.9465E+10 2485.51259

For GOAT conductor

Diameter=25.97mm

area E α θ1 θ2 uts t1 Ww W1 L W2 K1 K2 t24 787000 0.00001773 0 27 13780 6890 1731.33 2285.51 0.25 1492 -4480.9679 18249087167 5165.029896

4 787000 0.00001773 0 27 13780 6890 1731.33 2285.51 0.28 1492 -4291.5368 22081395472 5130.447887

4 787000 0.00001773 0 27 13780 6890 1731.33 2285.51 0.3 1492 -4084.0646 26278685520 5095.986649

4 787000 0.00001773 0 27 13780 6890 1731.33 2285.51 0.33 1492 -3858.5513 30840957312 5062.105154

4 787000 0.00001773 0 27 13780 6890 1731.33 2285.51 0.35 1492 -3614.997 35768210847 5029.174253

area E α θ1 θ2 uts t1 Ww W1 L W2 K1 K2 t34 787000 0.00001773 27 60 13780 5165.0299 1731.33 2285.51 0.25 1492 -1717.9825 18249087167 3347.007572

4 787000 0.00001773 27 60 13780 5130.4479 1731.33 2285.51 0.28 1492 -1320.0397 22081395472 3321.523033

4 787000 0.00001773 27 60 13780 5095.9867 1731.33 2285.51 0.3 1492 -879.60001 26278685520 3297.038878

4 787000 0.00001773 27 60 13780 5062.1052 1731.33 2285.51 0.33 1492 -396.04545 30840957312 3273.727475

4 787000 0.00001773 27 60 13780 5029.1743 1731.33 2285.51 0.35 1492 131.123311 35768210847 3251.692314

For SHEEP CONDUCTOR

Diameter=27.93mm

A(cm

2)

(kg/cm

3) α(/°C)

θ1(°C

)

θ2(°

C)

uts(kg

) T1(kg)

Ww

(kg)

W1

(kg)

L(k

m)

W2

(kg) K1 K2 T2(kg)

4.626 789000 0.00001773 0 27 18230 9115 1992.66 2807 0.25 1977 -6466.345 37150507074 7185.815008

4.626 789000 0.00001773 0 27 18230 9115 1992.66 2807 0.28 1977 -6277.05 44952113560 7155.09915

4.626 789000 0.00001773 0 27 18230 9115 1992.66 2807 0.3 1977 -6069.727 53496730187 7123.862

4.626 789000 0.00001773 0 27 18230 9115 1992.66 2807 0.33 1977 -5844.3758 62784356955 7092.489294

4.626 789000 0.00001773 0 27 18230 9115 1992.66 2807 0.35 1977 -5600.9966 72814993865 7061.319943

A(cm

2)

(kg/cm

3) α(/°C)

θ1(°C

)

θ2(°C

) uts(kg) T1(kg)

Ww

(kg)

W1

(kg)

L(km

)

W2

(kg) K1 K2 T3(kg)

4.626 789000 0.00001773 27 60 18230 7185.82 1992.66 2807 0.25 1977 -3599.9093 37150507074 5054.218408

4.626 789000 0.00001773 27 60 18230 7155.1 1992.66 2807 0.28 1977 -3249.5142 44952113560 5027.782175

4.626 789000 0.00001773 27 60 18230 7123.86 1992.66 2807 0.3 1977 -2863.3059 53496730187 5001.711194

4.626 789000 0.00001773 27 60 18230 7092.49 1992.66 2807 0.33 1977 -2440.8926 62784356955 4976.27278

4.626 789000 0.00001773 27 60 18230 7061.32 1992.66 2807 0.35 1726 -1981.9299 55499498831 4602.23391

Sag & height of tower calculation

Maximum sag Dmax =

;l is length of span in km

=

=3.8678m

hg =

+17 feet ; hg is min ground clearance

=

17 = 20.4 feet = 6.21m

Height of lower conductor (h1)=hg+Dmax = 10.9 m

Ht. of middle conductor (h2)=h1 + y =13.73 m

Ht. of top-most conductor (h3) = h2 + y =17.35 m

Total height of tower (ht)=h3 + d’ =22.32 m

Similarly, the maximum sag h1, h2, h3 and total height of tower are calculated and presented in the

table as below

Wc length Hg T3 Dmax h1 h2 h3 Ht

976 0.25 6.215 1971.386668 3.867835835 10.08283584 14.16583584 18.24883584 24.69933584

976 0.275 6.215 1927.945036 4.785535805 11.00053581 13.04203581 15.08353581 21.53403581

976 0.3 6.215 1888.465482 5.814244478 12.02924448 14.07074448 16.11224448 22.56274448

976 0.325 6.215 1852.828058 6.954908711 13.16990871 15.21140871 17.25290871 23.70340871

976 0.35 6.215 1820.790055 8.207975411 14.42297541 16.46447541 18.50597541 24.95647541

Wc length Hg T3 Dmax h1 h2 h3 Ht

1097 0.25 6.215 2306.079344 3.716399664 9.931399664 11.97289966 14.01439966 20.46489966

1097 0.275 6.215 2267.33455 4.57368681 10.78868681 12.83018681 14.87168681 21.32218681

1097 0.3 6.215 2231.515987 5.530433155 11.74543315 13.78693315 15.82843315 22.27893315

1097 0.325 6.215 2198.655619 6.587583794 12.80258379 14.84408379 16.88558379 23.33608379

1097 0.35 6.215 2168.666936 7.745685712 13.96068571 16.00218571 18.04368571 24.49418571

Wc length Hg T3 Dmax h1 h2 h3 Ht

1219 0.25 6.215 2616.750037 3.639414298 9.854414298 11.8959143 13.9374143 20.3879143

1219 0.275 6.215 2580.248364 4.465988444 10.68098844 12.72248844 14.76398844 21.21448844

1219 0.3 6.215 2546.163157 5.386045259 11.60104526 13.64254526 15.68404526 22.13454526

1219 0.325 6.215 2514.593542 6.400481472 12.61548147 14.65698147 16.69848147 23.14898147

1219 0.35 6.215 2485.512586 7.509894581 13.72489458 15.76639458 17.80789458 24.25839458

Wc length Hg T3 Dmax h1 h2 h3 Ht

1492 0.25 6.215 3347.007572 3.482588476 9.697588476 11.73908848 13.78058848 20.23108848

1492 0.275 6.215 3321.523033 4.246263645 10.46126364 12.50276364 14.54426364 20.99476364

1492 0.3 6.215 3297.038878 5.090931779 11.30593178 13.34743178 15.38893178 21.83943178

1492 0.325 6.215 3273.727475 6.017318989 12.23231899 14.27381899 16.31531899 22.76581899

1492 0.35 6.215 3251.692314 7.025956885 13.24095688 15.28245688 17.32395688 23.77445688

Wc length Hg T3 Dmax h1 h2 h3 Ht

1726 0.25 6.215 5054.218408 2.667944658 8.882944658 10.92444466 12.96594466 19.41644466

1726 0.275 6.215 5027.782175 3.245187079 9.460187079 11.50168708 13.54318708 19.99368708

1726 0.3 6.215 5001.711194 3.88217137 10.09717137 12.13867137 14.18017137 20.63067137

1726 0.325 6.215 4976.27278 4.579450275 10.79445027 12.83595027 14.87745027 21.32795027

For PANTHER

For LION

For BEAR

For GOAT

For SHEEP

Earth wire selection

Earth wire chosen is GUINEA

No. of strands = 19

Diameter of a strand = 2.92 mm

Wt. per kilometer = 590 kg/ Km

Conductor diameter = 14.6 mm

Conductor area = 127.20 mm2

Ultimate tensile Strength(UTS) = 6664 kg

Hence, maximum tension (Te) = UTS / 2 = 3332 kg

Bending moments and Tower Weight calculations

For PANTHER conductor

Let’s take 80% for tower A,15% for tower B;5% for tower C.

a) Due to earth wire

i. Bending moment acting on tower due to earth wire considering wind force :

Wind force due to earth wire (Few)= wind pressure * dia. Of earth wire

= 100*14.6*2/3*.25= 243.33 kg-m

BMEw=Few*Ht

=243.33*24.699= 6010.1717 kg-m

ii. Bending moment due to turning of earth wire

BMET=2*Te*(sin1:*0.8+sin7.5:*0.15+sin15:*.05)*Ht = 7704.756Kg-m

b) Due to power conductor

i. Bending moment acting on tower due to power conductor considering wind force

BMPw = Fw*(H1 + H2 + H3)* 2

=Fw(100*0.021*2/3*0.25)*(10.082+14.1658+18.2488)*2 = 29748.255 kg-m

ii. Bending moment due to turning of the power conductor

BMPT =2*(sin1:*0.8+sin7.5:*0.15+sin15:*.05)* (H1 + H2 + H3)* 2

=2*4563.5*42.4966*0.04648 = 36312.8342 Kg-m

c) Total Bending Moment (TBM)= BMEw + BMET + BMPw + BMPT

= .1717+7704.756+29748.255+29748.255 =79776.01746 Kg-m

Bending moment and tower strength calculation

span Ht De(mm Few BMEw BMEt BMPw BMPt TBM H1 H2 H3 dai(m) Wt of tower(tonS)

0.25 24.6993 14.6 243.333 6010.172 7704.76 29748.255 36312.83 79776.02 10.08284 14.166 18.249 0.021 6.225379172

0.275 21.534 14.6 267.667 5763.944 6717.37 30127.103 33432.07 76040.49 11.00054 13.042 15.084 0.021 5.298979451

0.3 22.5627 14.6 292 6588.321 7038.26 35458.276 36069.08 85153.94 12.02924 14.071 16.112 0.021 5.875416381

0.325 23.7034 14.6 316.333 7498.178 7394.08 41527.146 38993.07 95412.47 13.16991 15.211 17.253 0.021 6.533678211

0.35 24.9565 14.6 340.667 8501.839 7784.97 48405.558 42205.19 106897.6 14.42298 16.464 18.506 0.021 7.281343022

span Ht De(mm Few BMEw BMEt BMPw BMPt TBM H1 H2 H3 dai(m) Wt of tower(tonS)

0.25 20.4649 14.6 243.333 4979.792 6383.86 26651.675 34333.25 72348.58 9.9314 11.973 14.014 0.022 4.912120171

0.275 21.3222 14.6 267.667 5707.239 6651.28 31415.995 36791.59 80566.11 10.78869 12.83 14.872 0.022 5.400727953

0.3 22.2789 14.6 292 6505.448 6949.73 36827.656 39535.14 89817.98 11.74543 13.787 15.828 0.022 5.958272803

0.325 23.3361 14.6 316.333 7381.981 7279.5 42955.81 42566.61 100183.9 12.80258 14.844 16.886 0.022 6.5913033

0.35 24.4942 14.6 340.667 8344.353 7640.76 49869.212 45887.56 111741.9 13.96069 16.002 18.044 0.022 7.30660039

span Ht De(mm Few BMEw BMEt BMPw BMPt TBM H1 H2 H3 dai(m) Wt of tower(tonS)

0.25 20.3879 14.6 243.333 4961.059 6359.84 27895.919 37787.69 77004.51 9.854414 11.896 13.937 0.023 5.048649685

0.275 21.2145 14.6 267.667 5678.411 6617.69 32817.659 40413.32 85527.08 10.68099 12.722 14.764 0.023 5.536416355

0.3 22.1345 14.6 292 6463.287 6904.69 38390.122 43335.91 95094.01 11.60105 13.643 15.684 0.023 6.091041212

0.325 23.149 14.6 316.333 7322.794 7221.14 44681.808 46558.29 105784 12.61548 14.657 16.698 0.023 6.718716221

0.35 24.2584 14.6 340.667 8264.026 7567.21 51761.073 50082.37 117674.7 13.72489 15.766 17.808 0.023 7.425879979

span Ht De(mm Few BMEw BMEt BMPw BMPt TBM H1 H2 H3 dai(m) Wt of tower(tonS)

0.25 20.2311 14.6 243.333 4922.898 6310.92 30486.413 45433.22 87153.45 9.697588 11.739 13.781 0.026 5.32973848

0.275 20.9948 14.6 267.667 5619.598 6549.15 35716.645 48388.83 96274.22 10.46126 12.503 14.544 0.026 5.813134212

0.3 21.8394 14.6 292 6377.114 6812.63 41595.936 51657.91 106443.6 11.30593 13.347 15.389 0.026 6.358364953

0.325 22.7658 14.6 316.333 7201.587 7101.61 48189.84 55243.26 117736.3 12.23232 14.274 16.315 0.026 6.970803243

0.35 23.7745 14.6 340.667 8099.165 7416.25 55563.957 59146.94 130226.3 13.24096 15.282 17.324 0.026 7.656042396

span Ht De(mm Few BMEw BMEt BMPw BMPt TBM H1 H2 H3 dai(m) Wt of tower(tonS)

0.25 19.4164 14.6 243.333 4724.668 6056.8 30511.974 55934.01 97227.45 8.882945 10.924 12.966 0.028 5.402670912

0.275 19.9937 14.6 267.667 5351.644 6236.87 35336.633 58889.53 105814.7 9.460187 11.502 13.543 0.028 5.803770131

0.3 20.6307 14.6 292 6024.156 6435.57 40683.971 62150.94 115294.6 10.09717 12.139 14.18 0.028 6.251183881

0.325 21.328 14.6 316.333 6746.742 6653.08 46606.052 65721.06 125726.9 10.79445 12.836 14.877 0.028 6.748506104

0.35 22.4912 14.6 340.667 7662.011 7015.95 54739.779 71677.13 141094.9 11.95773 13.999 16.041 0.028 7.538989539

For PANTHER

For LION

For BEAR

For GOAT

For SHEEP

Cost per unit length calculation

Wt.= 0.00031*Ht√

=0.000631*24.699*√ = 6.225379172 tons

Cost of steel used in tower=Rs.150000/ton

Span=250m

No. of tower (N) = (total transmission length/span length )+ 1 =(100/0.25)+1 = 401

Cost/tower =cost per ton*wt. of tower =150000*6.225379= 933806.8758

Cost of tower/unit length =(933806.8758*401)/100= 3744565.572

Most Economical span and conductor selection wt. of steel =390kg/km wt. of Al = 586 kg/km tower cost/length =Rs. 2901191.249 cost of Al per ton =Rs.20150 total cost of power cond/length=

((20150*0.586+150000*0.39)*6) =Rs. 421847.4

capital cost(Rs)= 421847.4 + 2901191.249 =3323038.649

n=25year; i= 10%

annual cost(Rs) A =

=

=366092.7618

power loss/L(kw)=I2*R65*6 =253.22^2*0.16225*6 =62421.17864

L.F.=0.5; K1=0.2 ; K2=0.8; ; L.F is load factor

LLF= K1*L.F.+K2*L.F^2=0.3 ; LLF is loss of load factor

cost of energy loss/km=Power loss*LLF*TIME*rate per kwh

=62421.17864*0.3*365*24*7.5/1000

=Rs. 1230321.431

Total annual cost= 1230321.431 + 366092.7618 =Rs. 1596414.193

span(km Wt of tower(ton no.of tower cost/tower(Rs cost/length length cost steel used in tower/tower(rs

0.25 6.225379172 401 933806.8758 3744565.572 100 150000

0.275 5.298979451 365 794846.9177 2901191.249 100 150000

0.3 5.875416381 335 881312.4572 2952396.731 100 150000

0.325 6.533678211 309 980051.7317 3028359.851 100 150000

0.35 7.281343022 287 1092201.453 3134618.171 100 150000

span(km Wt of tower(ton no.of tower cost/tower(Rs cost/length length cost steel used in tower/tower(rs

0.25 4.912120171 401 736818.0257 2954640.283 100 150000

0.275 5.400727953 365 810109.193 2956898.554 100 150000

0.3 5.958272803 335 893740.9205 2994032.084 100 150000

0.325 6.5913033 309 988695.495 3055069.08 100 150000

0.35 7.30660039 287 1095990.059 3145491.468 100 150000

span(km Wt of tower(ton no.of tower cost/tower(Rs cost/length length cost steel used in tower/tower(rs

0.25 5.048649685 401 757297.4528 3036762.786 100 150000

0.275 5.536416355 365 830462.4533 3031187.954 100 150000

0.3 6.091041212 335 913656.1818 3060748.209 100 150000

0.325 6.718716221 309 1007807.433 3114124.968 100 150000

0.35 7.425879979 287 1113881.997 3196841.331 100 150000

Cost per unit length calculation

for PANTHER

For LION

For BEAR

span(km Wt of tower(ton no.of tower cost/tower(Rs cost/length length cost steel used in tower/tower(rs

0.25 5.32973848 401 799460.772 3205837.696 100 150000

0.275 5.813134212 365 871970.1318 3182690.981 100 150000

0.3 6.358364953 335 953754.743 3195078.389 100 150000

0.325 6.970803243 309 1045620.486 3230967.303 100 150000

0.35 7.656042396 287 1148406.359 3295926.251 100 150000

span(km Wt of tower(ton no.of tower cost/tower(Rs cost/length length cost steel used in tower/tower(rs

0.25 5.402670912 401 810400.6368 3249706.554 100 150000

0.275 5.803770131 365 870565.5197 3177564.147 100 150000

0.3 6.251183881 335 937677.5822 3141219.9 100 150000

0.325 6.748506104 309 1012275.916 3127932.579 100 150000

0.35 7.538989539 287 1130848.431 3245534.997 100 150000

For GOAT

For SHEEP

conduct

or

econom

ical

span

(km)

tower cost/

L (Rs) wt. Al

wt.

steel

Total cost of

PC

capital

cost(Rs)

annualo

cost (Rs) R65

p

loss/L(kw)

E loss

cost/L

total

ann.cost(Rs) R20

PANTHER 0.275 2901191.2 0.586 0.39 421847.4 3323038.649 366092.762 0.16225 62421.179 1230321.4 1596414.19 0.1375

LION 0.25 2954640.3 0.659 0.438 473873.1 3428513.383 377712.71 0.14431 55520.801 1094315 1472027.7 0.1223

BEAR 0.275 3031188 0.734 0.485 525240.6 3556428.554 391804.878 0.13004 50027.737 986046.7 1377851.58 0.1102

GOAT 0.275 3182691 0.896 0.596 644726.4 3827417.381 421659.194 0.10607 40807.562 804317.04 1225976.24 0.0899

SHEEP 0.325 3127932.6 0.104 0.69 633525.24 3761457.819 414392.557 0.0917 35278.18 695332.93 1109725.49 0.078

Most Economical span and conductor selection

since total annual cost of SHEEP is less ie.Rs.1131388.97 . So, we select DEER as our

conducter

Transmission Line Characteristic of the conductor SHEEP

SHEEP as our economical conductor. This conductor has 37 strand,30Al and &7 steel

R20 = 0.07771

α20 = 0.004

R65 = 0.0916978

PL= 0.587969 MW/conductor

η = 1 -

= 0.9679 (>94%)

Diameter=27.93 mm

GMRi=0.768*27.93/2=10.725mm

GMRc=D/2=13.965mm

GMD=√

Dab=√

Dab=√

=6.3084m

Dbc=√

6.3084m

Dca=√ =8.5027m

So GMD=6.968 m

R=0.0916978*100 = 9.16978

L=.2*ln(

)*L =.2*ln(

) *100

= 0.12953 H

C=

F/m

= 8.9503*10^-7 F

Z=R+jXl= 9.16978 + j*2*3.14*50*0.12953

=41.6932 < 77.294 °

Y=jXc =2.8103*10^-4 < 90⁰

Assuming ∏ model

A=D=(1+

)=.9942<0.0742°

B=Z=41.6932 < 77.294 °

C=Y(1+

)=2.802*10^-4<90°

Vs=A*Vr+B*Ir

=.9942<0.06559⁰*132000/√ + 41.6932<77.291° * 253.22<-18.195:

=81.1704<6.434: KV

VR=

= (81.1704/0.9942*√ -132)/132

= 7.129 %

Corrona inception voltage criterion

Vci(line)=√ *21.1*GMRc*m*δ* (

)

√ *21.1*1.3965*0.9*0.95*

=272.37 KV

Since Vci > 132*1.1kv,corona doesnot occur

A brief specification of the transmission line:

Power 110MW

Length 100km

Voltage level 132kv

No of circuit 2

No of conductor pre phase 1

Power factor 0.95

No of insulation discs 9

Conductor:-SHEEP

No of strands 37(30-aluminium & 7-steel) Diameter 29.89mm

Resistance(20°c) 0.0916978 Ώ/km

Inductance 0.12953 H

Capacitance 8.9503*10^-7 F

UTS 18230 kg

Weight of aluminium 1188kg/km

Weight of steel 789kg/km

LINE PARAMETER:

A 0.9942<0.0742°

B 41.6932 < 77.294 °

C 2.802*10^-4<90°

D 0.9942<0.0742°

Voltage regulation 7.129 %

Efficiency 99.512%

Corona inception voltage 272.37 KV

Span length 325m

Tower

Number 335

Weight of tower 6.748506104 Tons

Cost per length Rs. 3127932.579

Heights

Bending moments 125726.9kg-m

Power loss per unit length 35278.18watt

Energy loss cost per unit length Rs 695332.93

Total annual cost per length Rs 1109725.49

Maximum sag 4.579450275m

Ground clearance 6.215m

Height of lower conductor(H1) 10.79445m

Height of middle conductor(H2) 12.836m

Height of upper conductor(H3) 14.877m

Height of tower(Ht) 21.328m