Analysis of the electro-thermal effects of harmonics on cable joints based on the finite element method

When a cable is connected to the power grid, it is affected by harmonics. Once harmonics enter the cable, they can severely impact its operating condition and, in extreme cases, damage the cable equipment. In this paper, a three-dimensional simulation model of the cable and its joint is established based on finite element software, and simulations are carried out using the elector-thermal coupling module. By applying harmonics of different frequencies and varying harmonic contents to the cable joint model, an elector-thermal analysis under harmonic influence is conducted. Furthermore, the combined effects of the fundamental wave and various harmonic orders on the cable joint model are studied to investigate how the presence of harmonics under normal operating conditions affects the temperature and losses of the conductor at the joint. Simulation results show that as the frequency of the current increases, bot h the losses and the temperature of the cable and its joint continue to rise, and the higher the frequency, the faster the rate of increase.