With the continuous advancement of urbanization in China, infrastructure such as power cables, gas pipelines, bridges and tunnels, large buildings and urban underground utility corridors is growing rapidly, and the resulting fire safety issues are of great concern. In particular, with the rapid expansion of China's power grid, the level of power cable temperature monitoring urgently needs to be improved. Real-time distributed temperature monitoring of power cables can promptly detect abnormal local temperatures and analyze the insulation condition of lines, thereby preventing cable fires and ensuring continuous and reliable cable operation. It can also assist in calculating the steady-state ampacity of cables. Currently common power cable temperature measurement methods include temperature-sensing cables, point temperature sensors and infrared thermometers. Compared with traditional methods, distributed fiber optic temperature measurement has the advantages of long detection distance, anti-electromagnetic interference, flexible layout, intrinsic safety, simple installation and long service life, and has become the development trend of power cable temperature measurement.

Regarding the measurement distance and spatial resolution of distributed fiber optic temperature measurement technology, the fiber optic temperature measurement system performs online monitoring based on the Raman scattering effect. Through multiplexing and data preprocessing, it extends the sensing distance and improves spatial resolution, enabling zone-based monitoring of power cables. Establishing a distributed fiber optic sensing network for power cable temperature detection has practical applications.

The principle of distributed fiber optic temperature measurement includes the backscattering principle and optical time-domain reflectometry (OTDR) positioning technology. A time-division multiplexed distributed fiber optic temperature measurement scheme based on the Raman scattering effect was designed, with research and selection of key components such as pulsed lasers, wavelength division multiplexers and avalanche photodiodes. An embedded system with a microcontroller as the core communicates with the host computer via protocol, achieving reference temperature collection and channel switching under the control of the host computer. The host computer software realizes channel switching control, scattered signal acquisition, wavelet denoising, real-time dynamic temperature curve plotting and temperature database establishment.