The cathodic protection system together with coating on the pipe is general, however asphalt coating and/or coal-tar enamel has been substituted by polyethylene lining, which is good in quality, has very high electric insulation characteristics and therefore is widely used. As a result, high coating resistance has minimized the protective current required for the pipe. However, the tendency to increase the high voltage transmission line has resulted in A/C corrosion, A/C induction, and further, the damage of lightning is increasing and the countermeasures are highlighted. This article introduces the areas which need attention in design, and it provide examples and a review of some protection systems for effects suitable to the site. Finally we introduce some examples which have been very efficiently controlled.
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