Abstract: As hydroelectric generator unit cable systems are increasingly used in high-voltage, high-power applications, the impact of the electric field distribution and temperature variation at cable terminations on cable performance has gained significant attention. However, the differences in electric field distribution and temperature changes under varying harmonic content have not been adequately studied. This study addresses the lack of comparative analysis regarding the impact of harmonic content on the electric field distribution and temperature variation for both slip-on and cold-shrink terminations, as well as the issue of insufficient experimental validation of simulation results. The research conducts a detailed analysis of the electric field distribution, temperature variation, and their comparative behavior under different harmonic contents.