Question

State whether the following statements regarding transmission of power at high voltage are true or false.

a. It reduces volume of conductor required.

b. It increases transmission efficiency.

c. It decreases the cost of transformers, switchgear and other terminal apparatus.

1. (a) False, (b) True, (c) False
2. (a) True, (b) True, (c) True
3. (a) False, (b) True, (c) True
4. (a) True, (b) True, (c) False

Answer 1

Correct Answer - Option 4 : (a) True, (b) True, (c) False

Necessity of high voltage transmission:

• With the increase in transmission voltage, for the same amount of power to be transmitted current in the line decreases which reduces I2R losses. This will lead to an increase in transmission efficiency.
• With the decrease in transmission current, the size of the conductor required reduces which decreases the volume of the conductor.
• The transmission capacity is proportional to the square of operating voltages. Thus the transmission capacity of the line increases with an increase in voltage.
• With the increase in the level of transmission voltage, the installation cost of the transmission line per km decreases, but it increases the cost of transformers, switchgear and other terminal apparatus.
• It is economical with EHV transmission to interconnect the power systems on a large scale.
• The no. of circuits and the land requirement for transmission decreases with the use of higher transmission voltages.