Disc insulator of an electric power transmission line.
Relative permittivity of porcelain ε = 6,
Relative permittivity of cement ε = 2.
Dirt layer thickness 1 mm.
Dirt layer conductivity 30 uS/cm.
Calculate thermal effect of the leakage currents in the insulator.
Leakage current dendity distribution in the insulator (on the left), insulator temperature profile (on the right).