Transformer bushings are made from various materials to ensure electrical insulation, mechanical strength, and resistance to environmental conditions.
The material used often depends on factors such as the transformer’s voltage class, application, and design. Here are common materials and classifications for transformer bushings:
Porcelain Bushings:
Material: Porcelain is a traditional and widely used material for transformer bushings. It offers good electrical insulation properties and is resistant to environmental factors.
Classifications: Porcelain bushings are often classified based on their design and application, such as solid-core porcelain bushings, oil-impregnated porcelain bushings, and condenser-type bushings.
Composite (Polymeric) Bushings:
Material: Composite materials, often based on polymers or silicone rubber, are used to make bushings. These materials provide advantages such as lighter weight, resistance to pollution, and flexibility.
Classifications: Composite bushings may include categories like cycloaliphatic epoxy resin bushings or silicone rubber bushings. They are often classified based on their construction and insulating properties.
Oil-Filled Bushings:
Material: Bushings designed to be immersed in transformer oil are typically made of materials like porcelain or composite, with the oil providing additional insulation and cooling.
Classifications: Oil-filled bushings can be further classified based on their design and construction, such as cap-and-rod type, radial-fin type, or other configurations.
Dry-Type (Resin-Impregnated) Bushings:
Material: Dry-type bushings are often made with a solid insulating material, such as epoxy resin, and are not immersed in oil.
Classifications: Depending on the design and application, dry-type bushings can be categorized into various types, including capacitance-graded, capacitance-graded with a condenser core, or other configurations.
Capacitor Bushings:
Material: These bushings are designed with a condenser core to improve the capacitance grading and voltage distribution.
Classifications: Capacitor bushings are classified based on factors like the presence of a condenser core, which enhances their performance.
When selecting transformer bushings, it’s crucial to consider factors such as the transformer’s voltage class, environmental conditions, and specific application requirements.
