This paper presents a new proposed dynamic arc model of a non-uniform polluted insulator under HVACstress taking into account the dynamic arc characteristics. The model is based on a hybrid formulation ofObenaus model and the mathematical development of arc equations by Rizk combined with the dynamicequations of the change in arc resistance by Mayr. The model adopts the criterion of Hampton for arcpropagation and the model is simulated using MATLAB Simulink. The model can calculate the instanta-neous changes in arc current, arc length, arc resistance, and pollution level on insulator string at whichthe flashover occurs at certain voltage. Practical insulator geometries have been studied to demonstratethe model with non-uniform pollution in different positions and levels of pollution. The validity of themodel is verified by comparing the simulation results with the experimental results and previous works.