On the insulation resistance of an underground pipe-line: Polarization component and total resistance

Some approaches to theoretical treatments and empirical calculations of the specific polarization resistance r(pol) Of a buried steel electrode are co nsidered along with the calculations of the r(pol) Of an individual through defect in an insulation coating of a pipe-line and the total polarization resistance of a cluster of such defects. The limits of the applicability of a standard potential sensor to the determination of r(pol) (which are comm on in monitoring the efficiency of cathodic protection), as well as the lim its of the usability of the linearization of a cathodic curve in the estima tion of the polarization component R-pol of the insulation resistance R-ins of an underground steel pipe-line were indicated. The possibility of the i ndividual estimation of either of the two summand of R-ins through a modifi cation of the familiar method of the cathodic polarization of an electrical ly-cut section of a pipe-line, as well as the limitations on such measureme nts, and the advisability of a search for new methods of the estimation of R-ins are discussed.