Abstract: To investigate early warning methods for fires caused by power cable overheating, an experimental platform based on the time-domain reflectometry (TDR) method was established for locating localized overheating defects in cables. Both offline and online localization experiments were conducted, with the localization performance of the TDR method evaluated using localization error metrics. Results indicate that offline localization achieved an error rate not exceeding 1.86%, demonstrating excellent localization effectiveness. To enable online localization, a high-pass filter was configured between the cable and the TDR to suppress power-frequency interference and ensure high-frequency pulse transmission. This filter was designed as a 5th-order Butterworth high-pass filter with a cutoff frequency of 221.1 Hz and 60.21 dB attenuation at 50 Hz. Simulation and experimental verification confirmed it met design specifications. Online localization experiments revealed that the test signal injection efficiency remained high, with a measured positioning error of 7.8%. These research findings hold significant importance for preventing sudden large-scale power outages, effectively enhancing firefighting efficiency, and reducing the probability of cable duct fires.

Key words: time-domain reflectometry method, localized overheating, fault location, cable fires