Eexample of Cathodic Protection System for Steel Pipelines

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 quality, has very high electric insulation characteristic and therefore the mainstream now. As the result, high coating resistance has minimized the protective current required to the pipe. In the meantime the tendency to increase the high voltage transmission line has resulted in A/C corrosion, A/C induction and further the damage of lightning are getting bigger and the countermeasures to than are now highlighting. This article is to introduce the points which have to be paid attention in design, example and judgement of the some protection systems for effect suitable to the site. Finally we introduce some examples which have been very efficiently controlled.