Research Of Reference Temperature On Calibration Of Distributed Optical Fiber Temperature Sensor

Distributed optical fiber temperature sensor can realize measurement ofdistributed temperature field, which is used in temperature monitoring of electricequipment and fire monitoring of metro and tunnel widely and so on. As it is appliedin so many different fields, its temperature measuring accuracy requirement isincreasing. But, distributed optical fiber temperature sensor is not in temperaturemeasurement system and there is no calibration specification for it. Therefore,researching its operating principle and establishing calibration specification becomethe key to realize its temperature source. In this paper, reference temperature ofdistributed optical fiber temperature sensor is studied.Distributed optical fiber Raman temperature sensor is studied object and itstemperature measuring accuracy can be affected by several factors such as responsetime of analogue-digital converter and reference temperature. Through thetheoretical analysis, it is explained that reference temperature provide a referencepoint for distributed optical fiber temperature sensor and improve the system stability.Obtaining reference temperature accurately is an important premise ensuring systemtemperature measuring accuracy. The value and measurement error of referencetemperature all affect the system temperature measuring accuracy. Referencetemperature is very important on the calibration of distributed optical fibertemperature sensor.To improve the accuracy of reference temperature, one new equipment andmethod measuring the reference temperature is proposed. Two temperature sensorsare placed at the different position of container of optical fiber and the average valueof their measured temperature is reference temperature. Higher measurementaccuracy of reference temperature can be obtained using this new method andabnormal working state of the temperature sensors can be monitored.In order to determine the requirement of reference temperature measurementerror, a calibration experiment system is designed based on the theoretical analysis. Experimental results are extracted and analyzed after completing the experiment.Combining with theoretical analysis and experimental results, it shows that to ensurethe measurement accuracy at±1℃, the measurement error of reference temperatureis required at±0.5℃. Revising the experimental data and the result is closer to thestandard temperature, which is explained by developing a mathematical model.Finally, the conclusion for the research on this topic is made, it makes a certaincontribution for establishing calibration specification for distributed optical fibertemperature sensor. The next phase of the research work is prospected.