Recent developments related to the technology of ZnO varistors have
resulted in massive design improvements of the surge arresters.
However, there are still some misunderstandings on different
aspects of their energy handling capabilities, which include
thermal energy absorption capability and impulse energy
absorption capability [7]. The energy absorption capability is
defined as the amount of energy that a varistor can absorb without
failure [8, 9]. It is crucial to evaluate the energy capabilities as
over-specification of energy absorption capabilities will only result
in a reduction of the arresters’ protective characteristics because of
the high discharge voltage during surge events.
Several researches concerned with the energy absorption
capability of ZnO varistors have been published.
Ringler et al. have successfully demonstrated the energy absorption
capability as a function of the current magnitude of carrying out
destructive tests on various varistors used in station class surge
arrester. Significant findings on failure mechanisms of ZnO
varistors and their influences on the energy absorption capability
have been presented by Bartkowiak et al.