The arrester consists of ZnO tablet placed inside ceramic tube. Electrodes are connected to the end tablets.
An axisymmetric problem of Transient electric field.
Relative permittivity of air ε = 1.
Relative permittivity of ceramic ε = 2.
Relative permittivity of ZnO element ε = 60.
Conductivity of ZnO element - nonlinear.
Nominal voltage U0 = 35 kV.
Maximal current Imax = 520 A.
Surge voltage Umax = 200 kV.
Calculate the varistor current.
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 (IC>IR). At overvoltage (surge) IR prevails and varistor acts like a resistor. QuickField can calculate both active (IR) and reactive (IC) currents.
Surge impulse passing through the arrester
See the Telec2.pbm problem in the Examples folder.