The growth of discharges on polluted insulators

Dynamic model to predict AC critical flashover voltage of nonuniformly polluted insulators under thermal ionization conditions

“…By combining Eqs. (5) and (6), the temperature difference between the surrounding atmosphere and polluted layer on the surface of the insulator can be computed. The change in conductivity with temperature is an important factor that should be considered in the proposed model.…”

“…The analytical model of discharge as shown in Eq. ( 11) is applied to estimate the critical parameters of flashover on contaminated surfaces of insulators [5]:…”

“…Neumarker [4] then presented a modified version of the Obenaus model by using the uniform resistance per unit length of the pollution layer instead of a fixed resistance. Alston and Zoledziowski presented the mechanism of arc extinction by introducing quantitative criteria in terms of electric stress, pollution resistance, and leakage current under DC voltage [5]. Hampton introduced the discharge propagation criterion as a necessary condition for flashover [6].…”

A new proposed dynamic arc model for flashover performance of a non-uniform polluted insulator string under HVAC stress

“…It is noted that the values of the constants 23 and 0.4 used in Eq. (8) were obtained graphically as these values of constants have been calculated using the plot of dynamic voltage-current characteristic for the arc taken during laboratory tests.…”

“…Afterwards other researchers improved and developed the pollution-initiated flashover model under various conditions, and built up both static and dynamic AC/DC models [6][7][8][9][10][11]. Dynamic models mainly consider the arc channel as an equivalent electrical circuit and simulate arc propagation step by step.…”