Improving surface temperature measurement of the power cable and insulated busbar using the heat insulated layer

The surface temperature measurement is susceptible to the surrounding air for the cable or the insulated busbar laid in free air. Therefore, an approach for improving their surface temperature measurements by covering the temperature sensor with a heat insulated layer is put forward. Firstly, the surface temperatures of the cable and the insulated busbar attached by a platinum resistance thermometer with and without a heat insulated layer under rated current are obtained using the thermal analyses in Comsol. Subsequently, the temperature rise test of the insulated busbar was carried out for the indirect verification of the previous analyses. The measured surface temperatures were used to calculate the conductor temperature based on the transient thermal network. By comparison with the measured conductor temperature, it is found that the deviation of the surface temperature measurement without the heat insulated layer is about 4~7 K while that with the heat insulated layer is only ±1 K. Further, the generalization of the presented method to the distributed temperature sensing system is analyzed. This study demonstrates that the accuracy of the surface temperature measurement of the cable and the insulated busbar can be effectively improved by wrapping a suitable heat insulated layer around the sensor.