Hot spots of medium-voltage cable termination under harmonic voltages superposed on fundamental voltage

The effect of high-frequency harmonic voltage on the temperature and electric field of 35 kV cable termination is investigated and the relationship between hot spot and electric field distribution is analyzed. Voltages of different frequencies are exerted on the cold-shrinkable cable terminations of two types (stress grading and geometric) and it is found that, along with the increase of frequency, there are obvious hot spots on the stress grading termination, which are corresponding to the concentrating spots of electric field, while there is no obvious temperature change on the geometric termination. The electric aging test indicates that, along with the increase of aging time, the hot spot temperature of stress grading termination rises obviously while that of geometric termination is not so obvious.