From the 260–320 mA current range and higher ranks, the
highest peak frequency is recorded in the bushing and
the surge arrester with pollutant layer (Figs. 3a and c). The
lowest number of pulses on the surge arrester is because of
its longer leakage distance compared to that of the bushing,
which is about 69% as shown in Table 3. Therefore the
development of a pollution flashover is of lower probability
in the surge arrester than in the bushing. Based on this, the
pollution flashover process in polymeric insulation depends
mainly on both the leakage distance and the insulating
material type for the tested apparatus.