In [1]:

```
P = 5.0 #Power(MW)
pf = 0.8 #lagging power factor
d = 15.0 #Distance of line(km)
J = 4.0 #Current density(amp per mm^2)
r = 1.78*10**(-8) #Resistivity(ohm-m)
kV_1 = 11.0 #Permissible voltage level(kV)
kV_2 = 22.0 #Permissible voltage level(kV)
I_1 = (P*10**3)/((3)**(0.5) * (kV_1) * pf) #Load current(A)
area_1 = I_1/J #Cross-sectional area of the phase conductor(mm^2)
volume_1 = 3 * (area_1/10**6) * (d*10**3) #Volume of conductors material(m^3)
R_1 = r * (d*10**3)/(area_1 * (10**-6)) #Resistance per phase(ohm)
PL_1 = 3 * (I_1**2) * (R_1*10**(-3)) #Power loss(kW)
I_2 = (P*10**3)/((3)**(0.5) * (kV_2) * pf) #Load current(A)
area_2 = I_2/J #Cross-sectional area of the phase conductor(mm^2)
volume_2 = 3 * (area_2/10**6) * (d*10**3) #Volume of conductors material(m^3)
R_2 = r * (d*10**3)/(area_2 * (10**-6)) #Resistance per phase(ohm)
PL_2 = 3 * (I_2**2) * (R_2*10**(-3)) #Power loss(kW)
area_ch = (area_1-area_2)/area_1*100 #Change in area of 22kV level from 11 kV level(%)
vol_ch = (volume_1-volume_2)/volume_1*100 #Change in volume of 22kV level from 11 kV level(%)
loss_ch = (PL_1-PL_2)/PL_1*100 #Change in losses of 22kV level from 11 kV level(%)
print('For 11 kV level :')
print('Cross-sectional area of the phase conductor = %d mm^2' %area_1)
print('Volume of conductors material = %.2f m^3' %volume_1)
print('Power loss = %.2f kW' %PL_1)
print('\nFor 22 kV level :')
print('Cross-sectional area of the phase conductor = %d mm^2' %area_2)
print('Volume of conductors material = %.2f m^3' %volume_2)
print('Power loss = %.2f kW' %PL_2)
print('\nConductor size has decreased by %.f percent in 22 kV level' %area_ch)
print('Conductor volume has decreased by %.f percent in 22 kV level' %vol_ch)
print('Conductor losses has decreased by %.f percent in 22 kV level' %loss_ch)
```