QuickField
A new approach to field modelling

Industrial

Educational

Scientific

Sample problems

Examples gallery

Step-by-step tutorials

Verification examples

Programming examples

Distributive examples

Success stories

Customers

Main >> Applications >> Sample problems >> End winding insulation

End winding insulation

QuickField simulation example

The insulation material at the winding ends is often subjected to higher voltages than other parts of the winding. Solid insulation is used to subdivide long oil gaps into smaller ones.

Problem Type
Axisymmetric problem of AC conduction.

Geometry
End winding insulation Capacitor with non-ideal dielectric can be replaced by electric circuit with ideal capacitor and resistivity connected in parallel. 100 mm Grounded core SER Winding Oil Pressboard

Given
Relative permittivity of oil 2.2
Relative permittivity of paper 3.5
Relative permittivity of pressboard 4.5
Winding voltage = 200 kV (r.m.s.);
Static end ring (SER) voltage = 200 kV (r.m.s.);
Frequency f = 50 Hz.
Oil dielectric strength 20 kV/mm.

Task
Calculate electric field stress distribution in the oil gaps.

Solution
In QuickField we should specify peak voltage value, which is 200000*sqrt(2) V.
Dielectric conductivity is very low, comparing to the conductivity of the steel core. Zero conductivity is specified for all dielectric materials.
Electric field lines tool is used to construct XY-plot along the E-line.

Results
Electric stress distribution and electric potential lines.
Transformer end winding insulation electric stress