Ampacity Analysis and Calculation of Power Cable with the Impact of Cable Joint Considered

Power cable plays a critical role in modern urban grid, its operational reliability and ampacity are closely related with the temperature of cable core. Accurate calculation of the cable ampacity and temperature distribution are of great significance for reliability and economical operation of the power cable line. Cable joint fault accounted for a large proportion of power cable fault. Joints abnormal temperature rise, insulation damage and explosion occurs occasionally, result in part of the existing cable lines run in lower current carry capacity status than the design standards. This paper constructed a simplified model of the power cable joint structure, using the principle of heat transfer to establish a mathematical model of temperature field of power cable joint, using finite element method analyze the temperature distribution in power cable joints, and calculate the ampacity of cable for whether the cable joint was concerned or not, respectively. Results show that the cable ampacity values decreased for the impact of cable joint is considerate.