Self-calibration And Spatial Characteristics Of Distributed Optical Fiber Temperature Measurement Systems

In recent years,distributed fiber optical temperature measurement system has been widely used in the fields of tunnel,highway fire measurement,power cable measurement,oil-gas pipeline leak measurement etc.The accuracy requirement of distributed fiber optical temperature measurement system is increasingly improved.The traditional distributed fiber optical temperature measurement system has achieved real-time detection of fire,but the traditional system cannot reach technical index in extensive application.This paper improves the accuracy of the distributed optical fiber temperature measurement system by studying the self-calibration and the spatial characteristic.The main contents are as follows:(1)The temperature measurement principle of distributed optical fiber temperature measurement system is introduced.The self-calibration is designed and developed on the basis of the traditional distributed optical fiber temperature measurement system.The modules of DTS that has the self-calibration is selected,and the paper sets up a DTS.Processing system luminous power by using the cumulative average denoising algorithm and wavelet denoising algorithm,this paper compares system temperature measure accuracy.(2)After designing self-calibration system of DST,the paper proposes a method that determines system reference temperature by taking average in double digital temperature sensors.The T0 measuring method of constant-temperature bath and temperature detection device are introduced.A placed location of double digital temperature sensors is determined according to temperature test.By the PC control of heater band to heat,and read the T1,T2 value that from the digital temperature sensor in self-calibration system,and take the average of T1,T2 as the reference temperature of distributed optical fiber temperature measurement system.It can be improving effectively the measuring accuracy of the reference temperature.(3)The luminous power signal spatial characteristic is researched and the DTS long-distance temperature field is experimented on the basis of self-calibration system.Fitting attenuation formula that the luminous power signal of spatial field dose change with temperature test is based on a spatial characteristics study of 10km temperature field test curve.Temperature field is compensated according to the attenuation formula.After luminous power signal compensating,system's accuracy is enhanced obviously.It is not limited any more in distance and measuring temperature accuracy increase to 1?.The system reaches exact measuring temperature in long distance temperature field.