In this paper, an online steam pipeline leakage monitoring method, based on a weak-reflectivity optical fiber Bragg grating (wFBG) array for temperature-vibration hybrid sensing, is presented. This method meets the re-quirements of long-distance, large capacity, low false positive rate (FPR), and low false negative rate (FNR). The drawing tower online-writing FBG technology was used to write the wFBG (-40 dB), which has the advantages of high strength and good consistency. A large-capacity sensor network is realized using mixed time-division multiplexing and wavelength-division multiplexing technology. A novel temperature-vibration composite opti-cal cable structure was designed to realize multi-parameter pipeline leakage monitoring. A chirped wFBG array with a spatial resolution of 3 m and a narrowband wFBG array with a spatial resolution of 1 m were combined in the same optical cable to simultaneously monitor the vibration and temperature of the pipeline. Leakage of the steam pipeline is accompanied by changes in the temperature and vibration signals. The leakage and its location can be identified more accurately by changes in these two parameters in the wFBG wavelength and interfero-metric phase. The field experiment results show that this temperature-vibration two-parameter detection system can accurately identify and locate steam pipeline leaks and reduce the FPR. This validates the feasibility of the wFBG array-based temperature-vibration hybrid sensing technology for monitoring steam pipeline leakage.
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