Study on Abilities of the Current-cut-off Method to Eliminate IR Drops inherent in Cathodic Protective Potentials

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 V₀ (uncorrected). The feeding test curves were introduced as the methods to analyze the errors of I_SR and V₀. The effects of media resistivity and the stray currents on their values were also discussed.