zinc oxide varistor simulation, electric FEA finite element analysis of the varistor, lightning stroke protection with varistor
This is an example of the ZnO arrester simulation, performed with QuickField software. The arrester consists of ZnO tablet placed inside ceramic tube. Electrodes are connected to the end tablets.
Axisymmetric problem of transient electric.
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:
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 arrester acts like a resistor. QuickField can calculate both active (IR) and reactive (IC) currents.
|35 kV||0.67 mA|
|197 kV||433 A|
Surge impulse passing through the arrester