To assess the increasing risks of AC corrosion and overprotection on cathodically protected pipelines, new cathodic protection (CP) criteria have been proposed based on DC current density and AC current density measured using coupons. To evaluate the CP level considering those risks, a new hand-held instrument to measure DC and AC current densities as well as on- and instant-off potentials has been developed. In addition, a PC-based CP maintenance database has been also
developed to control the new instrument and analyze the measured data with respect to the proposed new CP criteria. A completely computerized system for the periodic CP inspection was developed by combining the innovative instrument and the new CP database which enables CP
maintenance activity to be performed more effectively and efficiently.