Conclusions
1.
Under conditions of desert pollution and wetness, the leakage current density along the contaminated layer on composite insulator for a given contaminant layer thickness and salinity (hence, conductivity) was computed and subsequently produced the total leakage current magnitude.
2.
The interrelationships between grain size, conductivity, and leakage current were estimated. The statistics of surface leakage current that depend on the probability distribution for those two independent variables (conductivity and grain size) was produced using a Monte Carlo technique. The log-normal distribution was found to best fit the leakage current statistical distribution, with mean value of 6.75 mA and standard deviation 2.1 mA in the present study case.
3.
A novel method is given to estimate the risk of flashover under pollution, where the cumulative probability density of the leakage current is used in this work as a direct tool for the risk of insulation failure.