Ac and transient electric field distributions along a 380 kV V-string insulator

This paper presents the results of a study of the ac and the transient electric field distributions along a 380 kV V-string of glass cap-and-pin suspension insulators. The transmission tower, conductors and insulators are modeled in 3D, and COMSOL 4.2 is used for the finite element simulations. The insulators are modeled both for clean and for the polluted cases. The pollution layer is modeled by a wet conductive layer of 2 mm thickness on the insulator surface and the conductivity of the layer is varied between 10^-8 to 1.0 S/m. The permittivity of the pollution layer is assumed to be 81. Clean, full pollution and partial pollution cases are taken into consideration. The effects of corona rings on the field distributions are also investigated by 3D simulations.