Calculations of the I x R-drop and potential variation along cathodically protected structures are needed to estimate the 'spread of protection' as well as the current delivery from anodes. Though the skilled use of a number of formulas available may give good results, detailed analysis is not possible. Furthermore their accuracy and reliability have frequently been questioned. In this paper results from computerized methods are presented. The finite difference and finite element methods have for years been applied successfully within several fields of engineering, but not to any extent in corrosion and, as far as is known, not at all in offshore cathodic protection. Two program modules utilizing such methods have been used for simulation of the cathodic protection of submarine pipelines. Effect of size, position and distribution of holidays in the coating have been evaluated and this of great importance with regard to protective level. The flow of current is also considerably restricted due to the higher resistivity of the sea-bottom mud even though the pipeline is not buried. It is concluded that computer simulation of this kind will be useful for checking and control, and for cathodic protection monitoring generally. (Wassmann)
Current and potential distribution on cathodically protected submarine pipelines
Strom- und Potentialverteilung bei kathodisch geschuetzten Unterwasserpipelines
North Sea Corrosion - what have we learnt. Trans I ; 97 ; 74-80
1979
7 Seiten, 8 Bilder, 1 Tabelle, 5 Quellen
Conference paper
English
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