Explaining the structure of transformer bushings:

Structure: Using an oil-paper capacitor core as the main bushing, the overall connection and main sealing of the bushing are achieved through cable-carrying current paths and the axial pressure generated by multiple sets of compression springs. The bushing connecting the oil storage tank is made of cast aluminum alloy to reduce hysteresis and eddy current losses, minimizing heating and temperature rise. 

The outer conical porcelain of the transformer bushing is a straight porcelain piece, with the umbrella-like part thinning out for a more attractive appearance. The umbrella-shaped part can still meet various pollution and insulation level requirements.

Transformer bushings are the main insulation devices outside the transformer tank. Due to different voltage levels, bushings can be porcelain, oil-immersed, or capacitor-type. So, how many types of transformer bushings are there?

The company details the types of transformer bushings for you below:

1.Resin-cast capacitor bushings

The main insulation of this bushing is also a capacitor core made of alternately wound insulation paper and aluminum foil, cast in epoxy resin to become a solid bushing. This type of bushing can be used as an oil-gas bushing, with its top mounted inside a GIS pipe filled with gas between them.

2.High current transformer bushings for 40kV and below

These bushings come in two structures: rod type and capacitor type. Medium generator transformer low-voltage winding outlets use rod-type pure porcelain bushings; large generator transformer low-voltage winding outlets use capacitor bushings.

40kV and below pure porcelain transformer bushings

These bushings also come in rod type and cable-penetration type structures. Rod type is used for transformer low-voltage bushings; 10~20kV high-voltage outlets use cable type.

3.Oil-paper capacitor transformer bushings for 66kV and above

The inner insulation of these bushings is a capacitor core made of alternately wound insulation paper and aluminum foil. Insulating oil fills the space between the capacitor core and the porcelain bushing. There are rod-type and cable-penetration type connections with the winding.