a Azimi.Montazer - M.s in control engineering ,pnu teacher
Mahdieh Abaszadeh - M.a in English translation , teacher
Roozbeh Rahmany - Sama technical and vocational training college,Islamic Azad University Ardabil Branch,Ardabil,Iran
Saeid Bairami - Sama technical and vocational training college,Islamic Azad University,Ardabil Branch,Ardabil,Iran

The concerns about corona due to its harmful effects and its impact on the power system are well known. Among them, the exposure of polymer insulators, reducing service life and leading to possible failures, is particularly worrisome. This paper presents an electric-field calculation model of a 230 kV composite insulators based on finite element method. The objective of this work is to comparison the effect of contamination on potential and electric field distributions along the insulator surface in presence of corona ring. This model introduces the effect of the corona rings on the potential and e-field distribution along the composite insulators. Finite element method (FEM) is adopted for this work. Also, a conductive layer on the insulator surface has been used in order to simulate the environmental pollution. The computation results show that the E-field distribution on composite insulators is nonlinear with the regions close to the energized end normally being subjected to the highest magnitudes.

Corona Ring, Electric field distribution, Finite element method, potential distribution