Laminated Wood in Oil-Immersed Transformers: Electrical Insulation and Mechanical Support

Laminated Wood in Oil-Immersed Transformers Laminated wood, also known as electrical laminated wood or insulation la...

Laminated Wood in Oil-Immersed Transformers

Laminated wood, also known as electrical laminated wood or insulation laminate, is a critical material used in oil-immersed transformers and instrument transformers. Its excellent electrical insulation, high mechanical strength, and customizable shapes make it ideal for supporting and isolating internal components. Laminated wood ensures the transformer operates safely and reliably under demanding conditions.

What is Laminated Wood?

Laminated wood is produced by impregnating high-quality birch wood veneers with insulating resin and then pressing them under heat. This process creates a dense, durable material that combines both mechanical strength and electrical insulation. Due to its versatility, laminated wood can be machined into various components such as:

Coil clamping plates
Support blocks
Insulating spacers
Core and coil supports

These components are widely used in oil-immersed transformers to maintain structural integrity and prevent electrical faults.

Manufacturing Process of Electrical Laminated Wood

The production of electrical laminated wood involves multiple precise steps:
Veneer Preparation: High-quality birch wood is sliced into thin sheets and dried.
Impregnation: Sheets are soaked in insulating resin through single or double impregnation.
Lamination: Sheets are stacked in cross-grain patterns to enhance mechanical strength.
Hot Pressing: The stack is pre-pressed and then heat-pressed under high pressure to form a solid laminate.
Machining: The laminated block is cut, drilled, and finished according to transformer component specifications.
This careful process ensures the laminated wood is strong, heat-resistant, oil-resistant, and dimensionally stable.

Key Roles of Laminated Wood in Oil-Immersed Transformers

Electrical Insulation

Even though transformers use insulating oil, certain structural parts such as coil frames, spacers, and supports require solid insulation. Laminated wood effectively isolates high-voltage and low-voltage regions, preventing:

Electrical breakdown
Partial discharge
Current leakage

This guarantees safe operation and long-term reliability.

Mechanical Support

Transformers experience strong electromagnetic forces during operation, which can cause coils to shift or deform. Laminated wood provides excellent:

Compressive and bending strength
Shear resistance
Structural stability

It keeps windings and components securely fixed, reducing vibration and mechanical stress.

Heat and Oil Resistance

Laminated wood is treated with insulating resins, giving it:
High thermal stability
Resistance to transformer oil corrosion
Long-term durability in harsh environments
This ensures consistent electrical and mechanical performance over time.

Environmental and Safety Benefits

As a renewable resource, laminated wood is environmentally friendly compared to synthetic insulation materials. Its reliable insulation properties also reduce the risk of electrical accidents, supporting safer transformer operation.

Easy Machining and Installation

Laminated wood is highly machinable and can be customized to precise transformer design requirements. This enables:
Fast assembly
On-site maintenance and replacement
Adaptation to complex structures
Its ease of use makes it a preferred material in transformer manufacturing.

Common Applications Inside Transformers

Coil clamping plates
Spacers and support blocks
Coil frame insulation
End winding support
Core and winding assembly components

Laminated wood is integral to almost every structural and insulating component of an oil-immersed transformer.

Conclusion

Laminated wood plays a crucial role in oil-immersed transformers by providing:
High electrical insulation
Strong mechanical support
Heat and oil resistance
Environmental friendliness
Ease of machining and installation
Its combination of properties makes it an indispensable material for transformer reliability and safety.