The Leakage Detection And Location Based On Raman Scattering Distributed Temperature Fiber Optic Sensor On Tap Water Pipeline Methods Research

The urban water pipeline distribution presents an increasing trend every year.The underground tap water pipeline is vulnerable to leakage due to soil corrosion,pipeline protection layer and man-made damage.The diversity of pipes and the complexity of the environment make it difficult to detect the leakage of tap water pipelines timely and accurately.It causes water cut-off,underground surface water and ground subsidence,which threatens the lives of residents.In this paper,the distributed optical fiber temperature measurement technology was used to study the water pipe leakage detection and location technology based on Raman scattering distributed optical fiber sensing.(1)The optical fiber sensing technology and the principle of fiber scattering were introduced firstly.Then,the structure and detection principle of the distributed optical fiber temperature sensor based on Raman scatter were studied.A leak detection method for tap water pipeline based on distributed optical fiber Raman temperature measurement was proposed.A simulation platform for water pipeline leak detection was built.(2)The data acquisition and processing module based on Microsoft Visual Studio platform was developed.The temperature signal obtained by the detection system.The denoising process of wavelet transform denoising was introduced.Denoising the temperature detection signal when the sensing fiber is 200 m.(3)A signal processing method based on clustering analysis and selective average threshold method was proposed for the temperature signal obtained by the detection system.The detection signals of the sensing fiber lengths of 500 m and700m were analyzed by cluster analysis method of absolute value distance.Accurately identified leaks and leaks in the tap water pipe.Then,using the selective average threshold method,the leak detection points of the sensing fiber 200 m and500m long leak detection signals were respectively located.By using this method,the leakage of tap water pipe was identified accurately,and false positive rate and false negative rate are reduced by 6% and 8% respectively.(4)Experiments were carried out on a buried tap water network simulation experiment platform using a distributed optical fiber temperature measurement system based on Raman scatter.These experiments included two-point leakage and three-point leakage measurements of the UPVC pipe,cast iron pipe and stainless steel pipe.Their diameters are 100 mm.The temperature signal were processed by selective average threshold.The difference signal of non-leakage position is between0 and 0.6,and the signal of leakage position is between 0.8 and 1.2.The experimental results show that the distributed fiber Raman temperature measurement system based on selective average threshold method can accurately identify and locate the multiple point leakage of tap water pipeline.