11-04-2017, 09:13 AM
The high voltage underground cables used in the National Grid system can be of three types: direct buried, channel or tunnel. Underground cables are used for power applications where it is not practical, difficult or dangerous to use the airlines. They are widely used in densely populated urban areas, in factories, and even to supply electricity from the general posts to the consumer premises.
Underground cables have several advantages over airlines; They have lower voltage drops, low chances of failure, and low maintenance costs. However, they are more expensive to manufacture, and their cost may vary depending on the construction as well as the voltage rating.