L51750 New Technique to Assess Level of Cathodic Protection in Underground Pipe Systems (Phases I and II)

This report introduces the Variable Frequency Impedance Tomography (VFIT) method for assessing the effectiveness of non-interruptible power supplies (sacrificial anodes) for protecting coated buried pipe.

This method imposes a low-amplitude alternating voltage between the pipe and a reference electrode placed on the surface. A potentiostat/galvanostat controls the electric potential by modulating the current between the pipe and a surface counter electrode. The principle interpretive tool used in this study was an Artificial Neural Network (ANN) that had been \trained\" on simulated pipe with a defective coating and on field data from a test pipe.