Varistor response under subsequent stroke-like impulse current

摘要

Varistors testing procedures are mainlyrnperformed with two current impulse types: The 8/20rnand the 10/350. However, neither the 8/20 nor thern10/350 impulse is able to reproduce the maximum riserntime observed in subsequent stroke lightning current.rnHence, it is necessary to study the varistor behaviorrnunder the application of fast di/dt lightning currents.rnFor this reason, the “Roman Generator”, a subsequentrnstroke–like current generator with a di/dt in the orderrnof 120 KA/ s was constructed. With the RomanrnGenerator fast impulses were applied to severalrnvaristor types and the voltage drop on their terminalsrnwas measured. In this paper we present the varistorrncurrent and voltage signatures obtained with thernapplication of such fast current impulses.