The arrester consists of ZnO tablet placed inside ceramic tube. Electrodes are connected to the end tablets.

Given: Relative permittivity of the air ε = 1.
Relative permittivity of the ceramic ε = 2.
Relative permittivity of ZnO element ε = 60.
Conductivity of ZnO element - nonlinear.
Nominal voltage U_{0} = 35 kV.
Maximal current I_{max} = 520 A.
Surge peak voltage U_{max} = 200 kV.

Problem: Calculate the varistor current.

Results: The arrester can be represented by the equivalent schema with resistor R and capacitance C connected in parallel.

At nominal voltage the arrester acts as a capacitance (I_{C}>I_{R}). At overvoltage (surge) I_{R} prevails and arrester acts like a resistor. QuickField can calculate both active (I_{R}) and reactive (I_{C}) currents.