Strongly robust approach for temperature monitoring of power cable joint

This study aims to monitor the temperature inside power cable joint, with strong robustness to variable thermal environments and uncertain thermal parameters of the joint. The model consists of two sequential steps, radial-direction temperature inversion in the cable and axial-direction temperature inversion in the conductor. The former part was improved by coating the cable with a heat insulated layer, whereas the latter one was optimised through a proper parameter selection. Afterwards, an outdoor cable joint temperature-rise test was carried out and the temperature obtained from the proposed approach agrees well with the measured one. With the great change in ambient temperature and wind speed during the test, the model accuracy remains almost constant, and this is due to the heat insulated layer and low sensitivity coefficient of the algorithm. Besides, if the thermal conductivity and volumetric specific heat of waterproof compound in cable joint are assumed to increase by nearly five times, the maximum changes in temperature monitoring are only 1.4 and 0.4°C, respectively. The results indicate that this approach can effectively overcome the effects of variable thermal environments and thermal parameter dispersion in joint, thus promoting practical applications in temperature monitoring for cable joints.