Overhead Line System vs Underground Cable System
|Overhead System||Underground System|
|1.The size of conductor for same amount of power
|1.The size of conductor is quite large in
|2.The amount of insulation is less as overhead
lines are open to atmosphere and hence air provides
the necessary insulation.
|2.Very high degree! of insulation is required
as the underground system is laid under the
ground hence area is very compact.
|3.Heat can be dissipated easily in the surroundings
lines are open to atmosphere.
|3.Heat dissipation is very difficult and. hence
number of insulating layers are added to the cable.
|4.Overhead system is very cheap as no insulation
coating is used over the conductors i.e., the conductors
used are bare
|4.Very costly, because a number of insulation
layers has to be used to provide sufficient insulation.
|5.Faults can be detected easily||5.Fault detection is very complicated.|
|6.Maintenance work is very simple.||6.Maintenance work is very complex.|
|7. It is used for long distance transmission.||7.It is used for short distance transmission
|8.Public safety is less.||8.Public safety is more.|
|9.Faces problems due to interference with neighbouring
|9.No interference with the communication lines.|
|10.They are liable to hazards from lightning discharges.||10.Not liable to the hazards from lightning
|11.This system can’t be used near submarine crossings.||11.It can be used near submarine crossings.|