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

A method for detecting the polarized potential of a buried pipe which is cathodically protected by rectified alternating current impressed upon the pipe. Each rectified protection current is periodically pulsed to an off state for a precise pulse duration and pulse period which are integral multiple...

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Hauptverfasser: WALCOTT, KENNETH J, THOMPSON, NEIL G, HELTON, STEVEN B, RUCK, GEORGE T
Format: Patent
Sprache:eng ; fre
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Zusammenfassung:A method for detecting the polarized potential of a buried pipe which is cathodically protected by rectified alternating current impressed upon the pipe. Each rectified protection current is periodically pulsed to an off state for a precise pulse duration and pulse period which are integral multiples of the period of the alternating current. The potential between the pipe and a reference electrode at the test site is sampled and analyzed to detect the polarized potential. It is analyzed to find the area under the portion of the waveform during which no off pulses are present and to use that area to detect the on potential. The area within the off pulse, after reactive spikes are eliminated, is subtracted from the on potential area to determine the IR drop potential. The IR drop potential is then subtracted from the on potential and the difference is displayed as the polarized potential.