# 基于Bragg光栅的电力电缆温度在线测量方法研究Research on Online Measurement Method of Power Cable Temperature Based on Bragg Grating

DOI: 10.12677/JSTA.2020.82007, PDF, HTML, XML, 下载: 222  浏览: 596  科研立项经费支持

Abstract: Based on the principle of temperature measurement of fiber Bragg grating, the online monitoring method for power cable temperature is studied. Through ANSYS finite element simulation, the inner temperature cloud diagram of the cable is obtained and the temperature rise equation of cable core temperature and skin temperature is established. Compared with IEC-60287 standard, it is proved that the temperature rise equation is more accurate, according to the experimental schematic diagram, to select the appropriate device and build the experimental system.

1. 引言

2. 光纤Bragg光栅的测温原理

${\lambda }_{B}=2{n}_{eff}\cdot \Lambda$ (1)

Figure 1. Sensing principle of fiber Bragg grating

$\Delta {\lambda }_{B}=2{n}_{eff}\Lambda \left(\frac{\Delta {n}_{eff}}{\Delta T{n}_{eff}}+\frac{\Delta \Lambda }{\Delta T\Lambda }\right)\Delta T$ (2)

$K={\lambda }_{B}\left(\frac{\Delta {n}_{eff}}{\Delta T{n}_{eff}}+\frac{\Delta \Lambda }{\Delta T\Lambda }\right)\Delta T=\frac{\Delta {\lambda }_{B}}{\Delta T}$ (3)

$\Delta {\lambda }_{B}=K\cdot \Delta T$ (4)

3. 电力电缆热路模型法

IEC-60287标准 [6] 提供了具有代表性的电缆缆芯温度计算方法。缆芯发出的热量在扩散过程中，要经过除导体以外的所有结构；介质损耗产生的热量则要经过金属屏蔽层、铠装层、外护套等几部分；金属屏蔽损耗产生的热量要经过铠装层和外护套，而铠装损耗所产生的热量则只经过外护套。根据电力电缆的传热分析，得出其热路模型如图2所示 [7]。

Figure 2. Power cable hot circuit model

$\begin{array}{c}{\theta }_{c}={\theta }_{e}+\left[\left(1+{\lambda }_{1}+{\lambda }_{2}\right)\ast {T}_{3}+\left(1+{\lambda }_{1}\right)\ast {T}_{2}+{T}_{1}\right]\ast {W}_{c}\\ \text{\hspace{0.17em}}\text{\hspace{0.17em}}+\left[\left(1+{\lambda }_{1}+{\lambda }_{2}\right)\ast {T}_{3}+{T}_{2}+0.5\ast {T}_{1}\right]{W}_{d}\end{array}$ (5)

4. 电力电缆的仿真分析法

Table 1. Cable material parameters

(1) 电缆横截面为标准圆形；

(2) 电缆材料参数分布均匀且属性不变；

(3) 边界温度均匀分布，设定为定值。

(4) 电缆层间紧密连接，忽略接触电阻。

Table 2. Cable structure parameters

Figure 3. Geometric model

Figure 4. Finite element of three-core cablemeshing

Figure 5. Temperature cloud image of three-core cable

Table 3. Cable skin temperature and cable core temperature under different excitation

Figure 6. The line diagram of skin temperature and cable core temperature was fitted

${\theta }_{c1}=1.374{\theta }_{e}-8.217$ (6)

5. 热路计算法与仿真计算法的比较

${\theta }_{c}={\theta }_{e}+\left(11.86{I}^{2}+5.73\right)×{10}^{-5}$ (7)

Table 4. The results of the two formulas are compared

${T}_{1}=P\frac{{\rho }_{{T}_{1}}}{2\pi }G$ (8)

${T}_{2}=P\frac{{\rho }_{{T}_{2}}}{2\pi }{G}_{0}$ (9)

${T}_{3}=\frac{{\rho }_{{T}_{3}}}{2\pi }\mathrm{ln}\left(1+\frac{2d}{D}\right)$ (10)

$T=\frac{1}{\lambda S}$ (11)

λ为导热系数，表1中已给出；S为形状因子。

$S=\frac{2\pi }{\mathrm{ln}\left(R/r\right)}$ (12)

$S=\frac{2\pi }{\mathrm{ln}\left({r}_{2}/{r}_{1}\right)-\frac{1}{3}\mathrm{ln}\left(3{r}_{0}/{r}_{1}\right)}$ (13)

Table 5. Thermal resistance coefficient modified after core temperature comparison

6. 在线温度监测系统的设计

Figure 7. System overall design block diagram

Figure 8. Cable temperature monitoring interface

Figure 9. Fiber Bragg grating temperature measurement system

7. 结束语

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