Distributed Temperature Sensor System Based On BOTDR

In recent years, with the rapid development of social economic and the increasing electricity consumption of residents and industrial, the stable and reliable power supply has played an important role in the overall economic development. Substation is a power system in which a number of devices are assembled and used to cut off or connect, change or adjust the voltage, control the flow of the electrical energy etc. It’s the key node of the modern power transmission system, the substation is a keyelement of guaranteeing the normal working of electrical network. The power equipment in a substation worked in the outdoor environment are not only eroded by rain and wind, but also endured the bad conditions due to the temperature varying when season changes. So it may result in imperfect contacts of the device connection and increasing the contact resistance. It may burst into flames which caused by generating heat under the high current condition, lead to negative effect for power supply safety and residential power utilization. So it ’s very important to measure and monitor the temperature of the substation in real-time.In this thesis, a novel method based on Brillouin optical time domain reflectometer(BOTDR) technique was proposed to measure the existing substation’s temperature. The contents are as follows:Firstly, a distributed optical fiber temperature sensing(DTS) system was set up, were the insulator’s electric insulation is realized through the space optical coupling system, signal is collected by using BOTDR, and the data’s analysis is using MATLAB.Secondly, the paper analyzed the light scattering phenomenon that occurs when the light beam propagating in the fiber and the spontaneous Brillouin scattering mechanism, gave the linear relationship between Brillouin frequency shift and temperature / strain, derived the formula of coupling efficiency in space optical coupling system(gap, lateral displacement, deflection angle, spot mismatch).In the end, the DTS system was constructed, and the functional parameters(the average number of ESA, the probe light pulse, scrambler, collimator) were discussed. The experimental results showed that the system combining the space optical coupling technique can realize distributed temperature detection with 10-m spatial resolution, 25-km sensing range and 2℃ temperature accuracy.