A new single-arc AC dynamic FEM model of arc propagation on ice surfaces

This paper presents an improved dynamic model based on the finite element method (FEM) for predicting AC critical flashover voltage (FOV) of ice-covered insulators during the melting period. The proposed model is implemented on the COMSOL Multiphysics™ FEM commercial software which is coupled with Matlab® for iterative calculation. The proposed dynamic model is based on the Obenaus/Rizk model, and deals with the case of a single arc established on an ice surface. The arc is modelled by its root which is considered to be an equipotential surface for which a voltage boundary condition is used, and whose propagation condition and arc propagation velocity are provided by the Hampton and Bondiou-Galimberti criteria. This new dynamic numerical model was validated by comparing the results obtained for the arc velocities and FOV with the corresponding experimental values available in the literature as well as with those obtained from actual mathematical dynamic models. A good agreement between the different results was obtained which confirms that this new dynamic numerical model is an effective tool for insulator dimensioning under severe ice accumulation.