Question

why a higher transmission voltage is advantageous.

Source voltage = 5V

Line resistance = 1 Ohm

Load resistance = 4 Ohm

Calculate the following for each

Current in the circuit

Power dissipated by the line resistance

Power dissipated in the load

Total power delivered

Ratio of power lost due to line resistance to power dissipated in the load

Answer 1

When we are transmitting same power, say 400 MW through a 100 MV lines, using the full capacity of 100 MV through each line, then the current will be less, which will reduced the transmission loss.

a)
Total resistance in the circuit, R = R1 + R2
= 1 + 4 = 5 Ohm
Source voltage, V = 5 V
Current in the circuit, I = V/R
= 5/5
= 1 A

b)
Power dissipated in the line resistance = I²R1
= 1² x 1
= 1 W

c)
Power dissipated in the load resistance = I²R2
= 1² x 4
= 4 W

d)
Total power delivered = 1 + 4
= 5 W

e)
Ratio = 1/4
= 0.25