A Distributed Optical Fiber Temperature and Strain Measurement Method

Abstract

The invention relates to a distributed type fiber sensor measurement method, and specifically relates to a distributed type fiber temperature strain measurement method. The method comprises the following steps of : (1), laying a temperature sensing fiber and a strain sensing fiber; (2), receiving a temperature distribution result and a Brillouin frequency shift distribution result; (3), carrying out alignment and interpolation to the temperature distribution result and the Brillouin frequency shift distribution result; and (4), judging whether a temperature peak exists in the temperature distribution result and determining strain distribution of a fiber in a temperature area. In the invention, a method of collecting data for post processing is used to replace direct detection, so that the problem of an increase of detection time is prevented effectively. Software carries out an adjacent data point cumulative average to data with high spatial resolution, so that the spatial resolution can be reduced effectively, and the accurate matching with the DTS spatial resolution is quickly realized through optimization of cumulative average points.

Description

technical field [0001] The invention relates to a measurement method of a distributed optical fiber sensor, in particular to a distributed optical fiber temperature and strain measurement method. Background technique [0002] Optical fiber sensing technology is a new type of sensing technology, which has the advantages of high measurement accuracy, anti-electromagnetic interference, intrinsic safety, distributed measurement, etc., and is widely used in fields such as electric power, petrochemical, structure, and fire protection. The distributed optical fiber sensor based on Brillouin scattering is a fiber optic sensor that has developed rapidly in recent years. The measurement of various parameters, such as the measurement of the temperature and strain of the cable, especially the Brillouin Optical Time Domain Analyzer (Brillouin Optical Domain Analysis, BOTDA) based on the stimulated Brillouin scattering effect, uses the optical path structure of the loop fiber, due to the ...

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Problems solved by technology

However, the measurement of Brillouin light intensity limits the detection distance of the sensor, and the light intensity detection is easily affected by external disturbances, light source output power jitter, and polarization state drift.

[0005] 2. Landau-Placzek ratio method (P.C.WaitandT.P.Newson, "Landau-Placzekratioappliedtodistributedfibresensing," OpticsCommunications, 122(4-6):141-146, 1996), this method simultaneously measures the Brillouin scattered light intensity and Strain-insensitive Rayleigh scattered light intensity, the temperature change is extracted by calculating the ratio of the two (Landau-Placzek ratio), but the measurement of Rayleigh scattered light limits the detection length and spatial resolution of the sensor, and the system complexity is significantly increased

Due to differences in optical fibers, the excess length settings of single-mode and multi-mode optical fibers cannot be completely consistent, and the length coordinates measured by DTS and BOTDA may be misaligned in physical space.

[0011] 2. Inconsistent sampling rate

Due to the difference in technical solutions between BOTDA and DTS, as well as the difference in instrument configuration, the sampling rates of the two devices are often inconsistent, which will result in different numbers of sampling points for the same fiber distance.

[0012] 3. Spatial resolution difference

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