Metal pipeline corrosion detection technology based on multi-frequency AC field fingerprint method based on phase recognition

Abstract

A multi-frequency alternating current field fingerprinting metal pipe corrosion detecting technology based on phase recognition comprises the following steps: applying excitation alternating current of which the frequency is from high to low to a measured pipe; enabling the current to gradually permeate from the outer wall of the pipe to the inner wall of the pipe under the action of the skin effect, wherein the amplitude and phase of a measured signal can be changed by existing of defects; and selecting the maximum phase angle of a series of voltage signals to solve the defect depth. The absolute defect depth can be measured, reference voltage, original voltage and original wall thickness do not need to be measured, the drift resistance is good, and the technology is suitable for long-time online monitoring.

Description

technical field [0001] The field that the present invention relates to is mainly oil and gas metal pipeline defect detection and on-line monitoring, and specifically relates to a kind of oil and gas metal pipeline defect depth detection and on-line monitoring technology. The specific technical scheme is: at both ends of the area to be tested of the metal pipeline to be tested, two current injection electrodes are fixedly installed at a certain distance, so that the current distribution in the area to be tested in the pipeline is distributed as evenly as possible; The measuring electrodes are fixedly installed, and two adjacent electrodes along the pipeline axis form a measuring electrode pair; the metal area of ​​the pipeline between the electrode pairs can be equivalent to a resistance, so under the action of the excitation current, the electrode pair will Generate a voltage; inject a set of AC excitation currents with frequencies from high to low into the metal pipeline unde...

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Problems solved by technology

[0016] The present invention is mainly aimed at the disadvantages that the current traditional DC field fingerprint technology cannot measure the absolute defect depth, needs to introduce a reference voltage to cause drift interference, and the temperature difference between the reference plate and the measured pipeline will introduce a large measurement error, etc., and proposes A Multi-Frequency AC Field Fingerprint Metal Pipeline Defect Detection Technology

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