Thermographic and Electrical Test of Medium Voltage Surge Arresters

The paper presents the results of a thermal test (conducted with thermographic camera, coupled with an electrical test) of medium voltage metal–oxide surge arresters. Surge arresters (for U_c=18 kV) were tested for the leakage current and surface temperature: for 5 minutes under state 50 Hz alternating voltage 18 kV. The surface temperature of the MOAs correlates with an increase in leakage current. The result shows that the 0.6 mA AC leakage current in the medium voltage metal–oxide surge arrester (18 kV) is above the stable operating point, and the loss of electrical power is higher than the effective heat dissipation in the arrester. After 5 minutes of high voltage impact U = 18 kV, the surface temperature of the surge arrester was (4.32±0.55) K higher than the initial temperature. The IR camera can be used to detect the faults of ZnO metal–oxide surge arresters that lead to an increase in surface temperature.