Cross Section of a Submarine/Underground HVAC Transmission Line Cable
Below is a photo of the cross-section of a decommissioned submarine transmission line cable. The cable was used in a 230kV inter-island, High Voltage AC transmission line, and had a capacity of around 220 MVA. The oil, which is used for cooling, flows inside the conductor, while a thick insulator insulates the conductor from the “ground”.
Constructing a submarine or an underground transmission line is very much expensive than overhead cable. It is also hard to maintain and repair, and induces high charging current once in operation (for AC system only). That is why it is used for special cases only, like in inter-island transmission system.
Posted in Transmission System