Surface electric strength of HV insulators by partial arcs

Presents the results of laboratory tests on the influence of partial arcs on the surface electric strength of insulators in the part which is not shunted by the partial arc. The test were carried out using 50 Hz alternating voltage for vertical and horizontal parts of insulators. The insulator consisted of an electric porcelain tube with outer diameter of 70 mm with electrodes of both big and small boundary curvature. The flashover path of the tested insulators was changed in the range from 50 to 120 mm. The length of shunted partial arc was changed in the range from 5 to 35 mm. The results of experiments and measurements indicate that there is a considerable correspondence between the surface strength of insulator and the length of shunted partial arcs