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Sample problems 

ZnO lighting arrester

This is an example of the ZnO arrester simulation, performed with QuickField software.

Problem Type:

Axysimmetric problem of transient electric.

Geometry:

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 U₀ = 35 kV.
Maximal current I_max = 520 A.
Surge peak voltage U_max = 200 kV.

Problem:

Calculate the varistor current.

Solution:

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 varistor acts like a resistor. QuickField can calculate both active (I_R) and reactive (I_C) currents.

Results:

Surge impulse passing through the arrester

View step-by-step tutorial.

Download simulation files:

Student's version	Professional version
telec2_stud.zip	telec2.zip