Electric field calculations of wet insulating surfaces

Presence of water droplets over the insulator surface enhances the electric field intensity and leads to electrical breakdown. This is important for outdoor insulation because the combination of moisture and contamination causes flashover at operating voltage; hence affects reliability of power delivery. Electric field has been calculated on insulating surfaces for different patterns of wetting. Simulations have been conducted by varying the number of water droplets, their relative positions and contact angle on the insulator surface in the sheath region. They are simulated using a 3D Electric Field Analysis computer package (Coulomb). One important outcome of this work, is that location of the water droplets with respect to electrodes and other droplets are crucial in determining the maximum E-Field intensity and hence the flash over voltage.