Simulation of metal oxide surge arresters behavior

Metal oxide surge arresters are used to protect medium and high voltage systems and equipment against lightning and switching overvoltages. Measurements of the residual voltage of the metal oxide surge arrester indicate dynamic characteristics, and specifically, the residual voltage increases as the current front time descends and the residual voltage reaches its maximum before the arrester current reaches its peak. For these reasons, the metal oxide surge arresters cannot be modeled by only a non-linear resistance, since its response depends on the magnitude and the rate of rise of the surge pulse. Several frequent dependent models have been proposed, in order to simulate this dynamic frequency-dependent behavior. In the current work three modes - IEEE, Pinceti-Gianettoni and Fernadez- Diaz - are examined using PSCAD. The residual voltage of each model, implying 5kA, lOkA and 20kA 8/20mus impulse current, is compared with the manufacturers´ datasheet. The models were also used to study the lightning performance of a distribution line; the arresters were implemented on every pole and was calculated their failure probability. The results show that all the models function with a satisfactory accuracy; the differences among the models arise in the difficulties of the parameters´ estimation.