Bushings,also called High voltage bushing are wire-out device that leads the high-voltage wire inside the transformer to the outside of the fuel tank. It is not only used as the grounding insulation of the lead wire, but also plays the role of fixing the lead wire. It is one of the important accessories of the transformer.

The high voltage bushing casing can be divided into an oil-filled casing bushings and a capacitor casing bushings.

Oil-filled bushings are similar to a pressure equalizing plate in a capacitive casing. The capacitor core in a capacitive bushing is a series of coaxial cylindrical capacitors. In an oil-filled bushing, the insulating paper has a higher dielectric constant than oil, thereby reducing the field strength at that location.

The oil-filled bushings can be further divided into a single oil bushings and a multi-oil bushings, and the capacitor bushings can be further divided into a rubber paper bushing and a oil paper bushing.


A bushing is required when the current carrying conductor needs to pass through a metal casing or wall of a different potential. According to this application, the bushing can be divided into a transformer bushing, a switch or a combination electric bushing, and a wall bushing. For this “plug-in” electrode arrangement, the electric field at the edge of the outer electrode (such as the intermediate flange of the sleeve) is very concentrated, and discharge often begins here.

The general oil-paper-capacitor transformer bushings produced by the company are rated at 40.5~1100kV, rated current is 630~8000A, and the outer casing insulation anti-fouling grade is complete. In order to meet the needs of the transformer export to Southeast Asia, a 40.5 kV to 252kV oil-paper capacitive transformer bushing with a discharge gap was also developed.

Our 363kV to 550kV short-tail oil-paper capacitive transformer (reactor) bushings for high-altitude applications meet the needs of power transformers and shunt reactors used in high-altitude and heavy-duty areas.

The company has also developed a 126 ~ 252kV oil-paper capacitive transformer bushing with voltage taps in accordance with IEEE C57.19.00, which meets the requirements of foreign transformer manufacturers for the use of casing, and can replace foreign casing.

Wall bushings are used in power stations, substations, laboratories, etc. for high voltage conductors to pass through walls or floors.

The specification of oil-paper capacitive wall bushings produced by the company is rated voltage 72.5~550kV, rated current is 630~2500A; high voltage jacket dry wall bushing specifications are rated voltage 40.5~252kV, rated current is 630~2500A, set The outer insulation of the pipe is of complete anti-pollution grade.

To measure the electrical performance of the bushing, the measuring terminal of the bushing can be led to the intermediate transition tank as required by the user.

The flanged low partial discharge pure porcelain bushings is used for the power input and distribution transformers to insulate and support. The company has reduced the partial discharge of casing and transformer through the unique semiconductor glaze technology, improved the mechanical properties of the bushings through the flange-bonded structure, and the unique sealing structure to ensure reliable sealing performance.

The flange type low partial discharge pure porcelain casing produced by our company has the rated voltage of 12~46kV and the rated current of 630~6000A. The outer insulation of the casing is designed according to the class IV antifouling grade, which can meet the high altitude of 3000m.

Our bushing type is various. According to different application,there are different type of bushing

Our creative design engineer can help customer focused on full implementation bushing designing services of all sizes according to customer’s request.

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