Distributed optical fiber Raman sensing system and method for gas pipe network leakage

Abstract

The invention belongs to the technical field of distributed Raman optical fiber sensing, and discloses a distributed optical fiber Raman sensing system and method for gas pipe network leakage. The device comprises a pulse laser, a wavelength division multiplexer, a sensing optical fiber, a photoelectric detector, and a data collection system. Pulse laser output by the pulse laser passes through the wavelength division multiplexer and then enters the sensing optical fiber, anti-Stokes light reflected by a sensor passes through the wavelength division multiplexer and then is detected by the photoelectric detector, one part of the sensing optical fiber is arranged in a thermostatic bath, and the thermostatic bath is used for carrying out thermostatic control on the sensing optical fiber located in the thermostatic bath; signals detected by the photoelectric detector are collected and demodulated through the data collection system, and distributed temperature field information along the sensing optical fiber is obtained. According to the invention, the system resolution is optimized, and the measurement precision is improved.

Description

technical field [0001] The invention belongs to the technical field of distributed Raman optical fiber sensing, and specifically relates to a distributed optical fiber Raman sensing system for pipe network leakage, which takes into account both long sensing distance and high spatial resolution. Background technique [0002] Pipe network transportation has become the lifeblood of modern industry and national economy. With the development of the gas pipeline network industry, the safety monitoring of the gas pipeline network has become increasingly serious. The gas pipeline network is gradually aging with the continuous growth of the service cycle, which leads to the hidden danger of leakage in the gas pipeline network. If it is allowed to develop, it will lead to major safety accidents. However, the current single-point, multi-probe, and single-parameter sensors cannot meet the large-scale and long-distance detection requirements of pipeline network transportation. [0003]...

AI Technical Summary

Problems solved by technology

At present, the positioning method of the distributed optical fiber Raman sensing system is optical time domain reflection technology, but due to the limitation of the pulse width of the light source, the sensing distance and spatial resolution cannot be balanced, and the optimal spatial resolution is only 1m

Since the leakage of the pipeline network will lead to changes in the temperature of the leakage location, the leakage of the pipeline network can be located through distributed temperature measurement, but when the spatial resolution of the distributed Raman sensing system in the prior art is large , the extremely small range of temperature changes caused by leakage is difficult to detect

[0005] Based on this, the present invention proposes a distributed optical fiber Raman sensing system and temperature demodulation method based on reconstruction layered analysis, which can solve the problem that the spatial resolution and sensing distance of the existing distributed optical fiber Raman sensing system cannot be balanced It is expected that the spatial resolution of the system will be increased to 1 cm, which will meet the needs of gas pipeline network leak detection.

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