Development of In Situ Techniques for the Detection of Corrosion of Copper Concentric Neutrals of Electric Cables in Underground Environments

The EPRI project described here is directed at the development of in situ techniques for measuring and detecting corrosion of copper concentric neutrals. Using a semiautomated experimental field site, measurements have been carried out on buried 50 m cables, that have demonstrated the utility of electrochemical polarization measurements in detecting and measuring the corrosion of buried CCN. The progress in the development of microprocessor instrumentation for carrying out such measurements in a simple manner is described. It has also been demonstrated that the polarization measurements can be carried out on operating cables. Techniques for the measurement of the voltage and current fluctuations of corroding electrodes (corrosion noise) are described. These techniques are being investigated for their use in the detection of corrosion of CCN cables. They have been applied to copper electrodes in the laboratory, and preliminary tests have been carried out on buried cables. The results show that fluctuations can be detected on corroding copper in conditions similar to those occurring in the field.