Abstract:
On potentials taken at the ground surface of cathodic protection (CP) for the buried pipelines are plagued with errors due to numerous IR drops. The current-cut-off methods were commonly used to correct these errors. But the OFF potentials reading by current-cut-off methods were not equal to true polarization potentials in some cases. In this paper, these errors were divided into two parts, marked as I
SR (corrected in OFF potential) and V
0 (uncorrected). The feeding test curves were introduced as the methods to analyze the errors of I
SR and V
0. The effects of media resistivity and the stray currents on their values were also discussed.