This paper deals with the two most used arresters models applied in digital simulations with the Alternative Transients Program, the conventional, and IEEE models. It presents a model analysis and parameter adjustment procedures to the conventional model. It also presents an application to both models of different types of current and voltage surges and even power frequency voltage, with a comparison of the results obtained with both models and with typical manufacturer data. While adjustment of the IEEE model was difficult and laborious, the conventional model presented a straightforward procedure. The results obtained show that there is a close agreement between the two models when the surge front time is above 1/2 μs. The conventional model always presents higher values for the limiting and residual voltages, and better agreement with the typical manufacturer data. Thus, the conventional model presents the advantages of simplicity and more conservative results.