MEASUREMENT OF THE POLARIZED POTENTIAL OF BURIED PIPELINE HAVING IMPRESSED CURRENT CATHODIC PROTECTION

摘要

AbstractA method for detecting the polarized potential of aburied pipe which is cathodically protected by rectifiedalternating current impressed upon the pipe. Each rectifiedprotection current is periodically pulsed to an off statefor a precise pulse duration and pulse period which areintegral multiples of the period of the alternatingcurrent. The potential between the pipe and a referenceelectrode at the test site is sampled and analyzed to detectthe polarized potential. It is analyzed to find the areaunder the portion of the waveform during which no off pulsesare present and to use that area to detect the onpotential. The area within the off pulse, after reactivespikes are eliminated, is subtracted from the on potentialarea to determine the IR drop potential. The IR droppotential is then subtracted from the on potential and thedifference is displayed as the polarized potential.