The energy absorption capability and time-to-failure of varistors used in station-class metal-oxide surge arresters

Varistors for use in station-class surge arresters were tested to destruction to determine their energy absorption capability at current levels ranging from 0.8 A/sub peak/ to 35 kA/sub peak/. Typical mean values increased from 400-600 J/cm/sup 3/ at the lower current end to 1600-2000 J/cm/sup 3/ at 35 kA/sub peak/. The product of the mean time-to-failure and the mean current was found to be a constant over five orders of magnitude. The varistor failure mode was found to be a characteristic of the current magnitude. It is recommended that standard test methods be developed for the energy absorption capability of metal-oxide surge arresters, and be included in relevant standards.