Current density estimation method of coated steel damaged portion of buried pipe, cathodic protection management method and apparatus,

摘要

PROBLEM TO BE SOLVED: To eliminate the need for access to the area around a damaged coating portion of an underground pipe and to evaluate alternating-current corrosion risks.;SOLUTION: When a current of the damaged coating portion 2 of the underground pipe 1 is estimated, a potential difference between a first reference electrode 14a on the ground surface directly above the damaged coating portion 2 of the underground pipe 1 at a predetermined distance d or on the ground surface at an optional distance from directly above it, and a second reference electrode 14b apart from the first reference electrode 14a by an optional distance g is measured by a direct-current and alternating-current voltmeter 13, respectively; a direct-current current I_DC and an alternating-current current I_AC are derived respectively from the potential difference using predetermined formulas (7), (8) or (7'), (8'); and a direct-current density and an alternating-current density of the damaged coating portion 2 are derived by dividing the currents by a predefined area S of the damaged coating portion.;COPYRIGHT: (C)2011,JPO&INPIT