doi:10.5194/ars-12-29-2014 © Author(s) 2014. CC Attribution 3.0 License. Modeling of electrical transport in Zinc Oxide varistors

Abstract. The electrical transport in zinc oxide (ZnO) varis-tors is analyzed using microstructural material modeling. The fully three dimensional current distribution is computed by means of a nonlinear equivalent circuit model represent-ing the assembly of current carrying grains and grain bound-aries of the material. The investigation focuses on the phe-nomenon of current filamentation due to inhomogeneities of the varistor microstructure. Numerical results highlight the importance of 3-D percolation effects in the modeling of varistor currents as well as that of the grain bulk resistivity which so far has been neglected in previous studies.