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根据电力电缆温度监测的需求,本文设计了基于非相干OFDR的分布式光纤温度传感器,并给出了在恒温和温度有突变情况下的仿真结果。由于拉曼后向散射信号微弱,噪声干扰严重,本文采用小波分析方法对测试信号去噪处理,提高系统的信噪比。为计算电缆导体的载流量,本文基于传热学基本原理,采用有限单元自动划分法建立电缆稳态温度场模型。结合电缆物性参数及外界环境因素,分析电缆各层及其周围敷设区域的稳态温度场分布情况,并提出了一种基于二分法的电缆导体温度计算方法,可实现电缆导体载流量的快速准确计算。
According to the demand of power cable temperature monitoring, this paper designs a distributed optical fiber temperature sensor based on incoherent OFDR, and gives the simulation results under the condition of constant temperature and temperature. Due to Raman weak backscatter signal and serious noise interference, this paper uses wavelet analysis method to denoise the test signal to improve the signal to noise ratio of the system. In order to calculate the current carrying capacity of the cable conductor, based on the basic principle of heat transfer, a steady-state temperature field model of the cable is established by the finite element automatic division method. Combined with the physical parameters of cables and external environmental factors, the distribution of steady-state temperature field in cable laying layers and its surrounding area is analyzed and a method of calculating conductor temperature based on dichotomy is proposed, which can achieve fast and accurate current carrying capacity of cable conductors Calculate.