Simulation Analysis of Multi-Physical Field Coupling of 110 kV AC High-voltage Cable Intermediate Joints Under Broadband Disturbance

In this paper, the temperature field distribution characteristics of 110 kV AC high-voltage cable joints under the condition of wide-frequency perturbation are investigated. Firstly, a simulation model of electric-magnetic-thermal multi-physical field coupling of AC high-voltage cable is established, and three forms of wide-frequency perturbation are classified and discussed. It is shown that the effect of sub-synchronous oscillation on the temperature distribution of AC high-voltage cables is limited under ultra-low frequency conditions. With the increase of frequency, the effect is gradually emphasized and the inhomogeneity of the temperature field distribution increases. Super-synchronous oscillations, on the other hand, lead to a sharp increase in the temperature of the AC high-voltage cable, accompanied by a significant skin effect. High-frequency resonance skin effect on the cable temperature saturation phenomenon, so the high-frequency resonance of AC high-voltage cable temperature change with frequency is not obvious. Super-synchronous oscillation conditions, cable insulation loss and conductor loss are larger, sub-synchronous oscillation mainly leads to increased conductor loss, while high-frequency resonance mainly leads to increased insulation loss. Therefore, the damage caused by super-synchronous oscillation to the AC high-voltage cable is the most significant, in the online monitoring of power cables, the phenomenon of super-synchronous oscillation should be given extra attention and importance.