SOLUTION

Advantages of EHV Lines

The main reasons for the adoption of EHV or in other words, the main advantages of the EHV are discussed as follows:

1. In a transmission line, the amount of power, distance, conducting material, and power factor are constant. Hence, if the voltage is increased, the line losses are decreased because losses are inversely proportional to the voltage.
2. If the losses are reduced because of higher voltage, naturally the efficiency of the line is increased.
3. Voltage regulation is improved due to a reduction in line loss.
4. The volume of the conductor is reduced as it is inversely proportional to the square of the line voltage. Hence, less conducting material is required.
5. Large power stations are required to transfer a large amount of power from generating stations to the load centers. Technically and economically, this is possible only at the range of EHV/UHV.
6. Generating stations are located in remote areas from the point of view of economy, feasibility and safety purposes. Hence, EHV transmission is unavoidable for the transmission of large amounts of power from these stations to the load centers.
7. The EHV transmission is flexible because there is a possibility of future system expansion.
8. The transmission capacity of a line is increased greatly by the use of EHV/UHV. However, the cost of the transmission line and terminal equipment also increases with increasing voltage, but generally, these costs are directly proportional to the transmission voltage rather than the square of the transmission voltage. Further, this is saving in the cost due to a reduction in the energy loss in the line. Overall there is a reduction in cost with an increase in transmission voltage.
9. The interconnection of power systems on a large scale is possible with the use of EHV.
10. The load-carrying capability of the line is given as surge impedance loading (SIL) which is directly proportional to the square of the voltage. Hence, the increase in voltage results in more SIL and more power transfer capacity.
11. With the increase in the voltage, the number of circuits and land requirements is reduced greatly.