How A Transformer Bushing Working
Internal structure of a transformer bushing
The internal structure of a transformer bushing mainly consists of: a core for conducting current, a "heart" providing insulation, and external support for connection and fixation. The core function is to allow the high-voltage conductor to safely "penetrate" the grounded transformer tank.
working principle of a transformer bushing
The working principle of the bushing is as follows:
If you consider the transformer as a giant "electric kettle," it contains high-voltage electricity, and the outer shell is grounded metal (zero potential).
The fundamental task of the bushing is to safely guide the high-voltage electricity from the "kettle" to the outside using a "straw," without leakage.
The core challenge is: if a high-voltage wire is directly passed through a hole in the metal shell, at the edge of the hole, the high-voltage electricity will desperately "drill" towards the grounded shell, generating intense "electric sparks" (i.e., electric field concentration, leading to breakdown).
The bushing is like a "clever and robust multi-layered straw," solving this problem with the following three-layer design:
Inner layer (voltage equalization layer): Dissipating pressure.
This is the smartest layer. It is not simple plastic, but rather multiple layers of "insulating paper sandwiching metal foil" wrapped around the conductive rod, forming a capacitive voltage divider structure. It evenly distributes the huge voltage difference between the "inside" and "outside" of the transformer (e.g., 220,000 volts) into hundreds of tiny voltage steps. Like transforming a steep cliff into a gentle staircase, the electrical "pressure" is evenly distributed, preventing it from exploding at a single point.
Middle Layer (Insulation and Sealing Layer): Sealing and Support
This is a robust ceramic or composite material tube that encloses and seals the "inner layer." It serves two purposes: first, absolute insulation, ensuring the high-voltage electricity is firmly locked inside; second, mechanical support and sealing, like a bottle stopper, firmly fixing it to the transformer casing to prevent leakage of the internal insulating oil.
Outer Layer (Protective Layer): Resisting the External Environment
The part exposed to air has a specially designed surface (such as a ceramic umbrella skirt or silicone rubber) to prevent rain, dirt, and flashover. Like coating a straw with a waterproof layer, it ensures that current won't run along the outer wall when it rains or gets dirty.
Products Description
40.5kV bushing insulator is suitable for three-phase AC systems power stations and substation distribution equipment with a rated voltage of 40.5kV and a frequency of 50~60Hz. It is used to allow conductive parts to pass through partitions, walls, or other grounded objects, and serves as an insulation support and fixed connection between external conductors (busbars).
Contact Us
Shaanxi West Power Tongzhong Electrical Co., Ltd.
Contact: Melody Sun (Export Sales manager)
Email: xdtz03@westpowerelectric.com
Mobile: +86 180 9176 5658 (WhatsApp/Wechat)
