Overhead vs underground lines – Advantages and disadvantages

Overhead transmission system

Advantages

• High Power transmission.
• Low installation and material cost.
• Long-distance transmissions.
• The fault or damage in overhead lines can easily locate.
• Maintenance of the line is easier.
• Extension or joining on overhead lines can be performed easily and also it facilitates easy replacing.

Disadvantages

• As it is exposed to the surroundings the safety risk is high.
• A continuous pathway for the line creates obstructions.
• Vulnerable to lightning strikes

Underground transmission system

Advantages

• The underground transmission systems are safer than the overhead transmission system.
• Safer from lightning.
• It creates no obstructions.

Disadvantages

• The installation process through various geographic areas has high difficulties, because of ground excavation.
• The installation cost of Underground transmission is high, as it requires a continuous trench or concrete ducts for cable installation. Also, it has a high material cost due to the requirement of thick and insulated conductors.
• Underground transmission systems have a high cost of maintenance. Because the line needs to dig up before any repair activities and required to reinstall again.
• High complications in fault detection and maintenance.
• High voltage transmission is difficult in underground transmission.
• Limited by thermal capacity.