Use FFT Method for the Detection and Characterization of Pipeline’s AC Stray Current Interference

摘要

Use FFT (Fast Fourier Transform) data signal processing method for the detectionand characterization of oil & gas pipeline’s alternating voltage stray currentinterference. The results showed that this method is capable of distinguishing powerfrequency AC (alternating current) stray current interference from the dynamic DC(direct current) stray current of the pipeline. It can easily pick-up the DC part and ACpart of specified frequency. The experiments carried out in laboratory and fieldshowed that the result gained by FFT method is the same as that by conventionalinstruments, which is designed of analog filter circuit. And the carbon steel workelectrodes under natural corrosion showed its potential change toward more activedirection after the AC voltage is added on. All the above showed that the FFTmethod is an ideal tool for the detection and characterization of the buried pipeline’sAC stray current.