How does lighting arrestor work at transmission tower, when lighting strike take place?

Question

How does lighting arrestor work at transmission tower, when lighting strike take place?

Answer 1

Electric power system lightning protection

High-tension power lines carry a lighter conductor (sometimes called a 'pilot' or 'shield') wire over the main power conductors. This conductor is grounded at various points along the link, or insulated from the tower structures by small insulators that are easily jumped by lightning voltages. The latter allows the pilot wire to be used for communications purposes, or to carry current for aircraft clearance lights. Electrical substations may have a web of grounded wires covering the whole plant.

http://en.wikipedia.org/wiki/Lightning_r...