Evaluation of electrically stressed composite insulators contaminated by dry and wet sand

The present paper investigates the performance of composite insulators working in desert areas. The role of humidity, in characterizing electric field distribution over the dusty shed of such insulator, is illustrated via Finite Element approach. A 2D model for a real long-rod composite insulator is constructed. The model is built to simulate composite insulator in clean and polluted conditions. The maximum field is computed for several dielectric constants according to the humidity of the surrounding air. The change in the restricted angle, between the incident and refracted field lines at the shed/dust boundary, is used as an indicator for the field stress variation in this interfacing area. The impact of applied voltage on the stress distribution is also investigated. Finally, the difference in field between clean and dusty composite insulators is illustrated for a number of permittivities.