Research On Distributed Fiber Optic Temperature Measurement System And Its Application In Water Supply Pipe Leakage Monitoring

Distributed optical fiber temperature measurement system(DTS)has the advantages of distributed monitoring,anti-electromagnetic interference,corrosion resistance,etc.,and is widely used in water conservancy,electric power,civil engineering and other fields.With the development of social economy and the expansion of urban scale,the underground water supply pipeline network is also becoming more and more huge and dense,which will produce huge economic losses and serious social impacts once damage occurs.Traditional water supply pipeline leakage monitoring technology has several fundamental defects,especially point measurement,which has limited information,and it is vulnerable to electromagnetic interference,environmental impact,etc.,and also difficult to achieve intelligent monitoring needs.Therefore,the distributed fiber optic temperature measurement system was firstly designed,demodulated method studied,noise and signal processing,visualization software development,etc.This article was then applied to the pipeline leakage monitoring of nuclear energy water supply phase II project in Haiyan County,Zhejiang Province,and achieved good results.The main contents and results of this article are as follows:(1)Based on the principle of distributed fiber optic temperature measurement and demodulation methods,the overall structure of the self-researched distributed fiber optic temperature measurement system was determined;and based on the four key technical indicators of the system,the selection of modules for the system was carried out,and the overall construction of the independently designed DTS host was completed;the performance of the system host was tested,and the temperature measurement accuracy was ≤±1℃,with a spatial resolution of 1m,and the temperature resolution of 0.1℃,the host performance to meet the engineering requirements.(2)To analyze the noise and stability of the newly developed DTS,and subsequently propose a system noise optimization scheme,including: cumulative averaging algorithm for noise removal,wavelet transform modulus maxima method for noise removal,and the sectional setting method of attenuation compensation for optical fiber,and experimentally analyze the application effects of these methods on improving signal-to-noise ratio and stability through the self-researched system.(3)The developed DTS system software has the functions of temperature measurement alarm and pipeline leakage monitoring scenario visualization.By simulating three alarm scenarios,it is obvious that the DTS system provides timely alarms for abnormal conditions such as rapid temperature rise and high temperature rise,and accurately locates the location of fiber breakage.At the same time,in the actual operation of pipeline leakage monitoring of the second phase of nuclear energy water supply project in Haiyan County,the DTS system also successfully and accurately feedback the temperature and location information of the point where the fiber breakage failure occurred.(4)The laying and installation of eight temperature measurement fiber optic cables for pipeline leakage monitoring of the second phase of nuclear energy water supply project in Haiyan County were completed,totaling 12 km,with 100% survival rate of temperature measurement fiber.(5)The temperature distribution curves of eight pipelines in the second phase of nuclear energy water supply project in Haiyan County show that the DTS system is well applied in this pipeline leakage monitoring project,and no obvious leakage points are found.