Abstract: As the core power source of the electricity system, thermal power plants feature extensive and complex internal cable networks, which serve as key carriers for electricity transmission and distribution. A certain power plant heavily relies on high-capacity cable lines for external power transmission, and the safe and stable operation of these cables is directly critical to the safety of the plant and even the regional power grid. Therefore, implementing effective cable condition monitoring holds significant engineering importance and practical value in preventing major accidents and ensuring reliable power supply. Although the mechanisms of cable failures are diverse, their progression is commonly accompanied by abnormal heating in the cable body or joints. This makes real-time temperature monitoring one of the most direct and effective means to diagnose potential defects and warn against operational risks. The cable tunnel environment of outgoing lines in thermal power plants is focused on. In response to the limitations of traditional temperature measurement methods in terms of continuity, coverage, and intuitiveness, the application of visual temperature sensing technology is emphasized. Such sensors integrate intuitive temperature field imaging, highly sensitive real-time perception, and flexible, convenient deployment characteristics, enabling panoramic and non-contact temperature monitoring of the entire cable route and critical joint points within the tunnel. Research shows that the application of this technology significantly enhances the intelligence level and early-warning response speed of cable condition monitoring, providing robust technical support for the refined maintenance and proactive safety defense of cable systems in thermal power plants.