Polluted insulator flashover model for ac voltage

Considerable theoretical and experimental research on polluted insulators has yet to yield a perfect generalized mathematical model which can predict accurately critical flashover voltages and currents. In this paper an ac model has been proposed especially applicable to static arcs. The salient feature of the proposed model is that it takes into account the appropriate selection of arc constants for different chemical nature of the pollutants. The computed results closely follow the experimental curves and can predict rms value of critical flashover voltages with a mean absolute error (MAE) of <4%. The validity of the model was verified by comparing the computed results of rms critical flashover voltages and currents against experimental and theoretical data of other researchers for a number of practical insulators of different geometries and good agreement has been obtained