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# Bushing insulator

Bushing insulator electric stress distribution, 3 phase transformer insulation, three phase transformer insulation

3-phase bushing insulators 10kV rated are installed on the transformer tank cover.

Problem Type electrostatics.

Geometry 3D extrusion. Given
Relative permittivity of air ε = 1,
Relative permittivity of oil ε = 2.2,
Relative permittivity of insulator ε = 6,
phase A electric potential UA = 10000·√2/√3 · cos(0) = +8165 V,
phase B electric potential UB = 10000·√2/√3 · cos(120) = -4082 V,
phase C electric potential UC = 10000·√2/√3 · cos(240) = -4082 V.

Find the maximum field strength at the insulator and the electric field distribution.

Solution
To find the maximum field strength it is enough to simulate the electrostatic field at the moment of maximum voltage at the specific phase insulator. Phase A insulator maximum field simulation is presented (for phases B and C similar approach should be used).

Results
Electric field strength distribution at the surfaces of the insulators is presented at the picture below. • Video: Bushing insulator
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