The realities of underground cables

The replacement of overhead lines by underground cables is one of the most emotive topics of discussion in the field of electrical power engineering. One thing is clear: it is very much more expensive - perhaps by up to 20 times - to install major supergrid transmission circuits underground than overhead on towers. Even so. this extra cost represents only part of the difficulty, since such circuits can impose severe technical problems on the design of the transmission system and also restrictions on the way in which it may subsequently be operated.