How to choose Crepe paper tube for oil-immersed transformer?

When purchasing Crepe  paper tubes for oil-immersed transformers, factors such as material properties, technical para...

When purchasing Crepe  paper tubes for oil-immersed transformers, factors such as material properties, technical parameters, use environment, and supplier qualifications need to be considered comprehensively. The following is a specific purchase guide:

1. Core purchase points

Oil resistance requirements
Oil-resistant insulating paper materials (such as specially treated kraft paper or synthetic fiber paper) must be selected to ensure that they will not swell, decompose, or deteriorate when immersed in transformer oil (mineral oil or synthetic oil) for a long time.
Test standard: Check whether it passes the oil resistance test (such as ASTM D3455 or IEC 60554 standards).
Electrical insulation performance
Breakdown voltage: It must meet the transformer design voltage level, and the breakdown strength is usually required to be ≥40kV/mm (in oil-immersed environment).
Dielectric constant: Match with transformer oil to avoid uneven electric field distribution.
Mechanical strength
The oil-immersed environment may reduce the mechanical properties of the paper tube. It is necessary to select materials with high tensile strength (≥80N/mm²) and compressive strength to ensure that it will not deform or crack during long-term operation.
Temperature resistance grade
The oil-immersed transformer has a high operating temperature, and the paper tube needs to withstand 105℃~130℃ (normal oil temperature) for a long time, and the high-temperature model needs to withstand **150℃** or more.
Size matching
Select the inner diameter, thickness and length according to the winding size to ensure that the paper tube fits tightly with the winding to avoid excessive oil gap affecting heat dissipation or insulation performance.

2. Key technical parameter verification

Material: Oil-resistant insulating paper (such as crepe paper) requires proof of material composition
Withstand voltage level: ≥1.5 times the rated voltage of the transformer, for example, ≥50kV for a 35kV transformer
Thickness: 0.5mm~3mm (adjusted according to the voltage level) A thicker paper tube should be selected on the high-voltage side
Expansion rate: The expansion rate after oil immersion is ≤5% to avoid structural deformation caused by expansion
Moisture content: ≤0.5% (drying treatment) to prevent excessive moisture in the oil

3. Supplier evaluation and testing

Qualification certification: Suppliers must have ISO 9001 quality management system certification, and their products must comply with IEC 60641 or GB/T 5591.2 standards.
Test report: Oil resistance test report, breakdown voltage test report and mechanical strength test report are required.

4. Sample testing

The following tests are performed on the samples:
Oil immersion aging test (simulating long-term oil immersion environment);
Thermal stability test (performance retention ability at high temperature);
Mechanical strength verification (simulating deformation under winding pressure).

5. Use scenario adaptation

Outdoor transformer: choose wrinkled paper tubes with moisture-proof and UV-resistant treatment.
High-load transformer: give priority to synthetic fiber paper tubes with high temperature resistance and high mechanical strength (such as aramid paper).
Compact design: choose thin-walled (0.5mm~1mm) but high-strength paper tubes to save space.

6. Precautions

Compatibility verification: ensure that the wrinkled paper tube is compatible with transformer oil (such as mineral oil, silicone oil or ester oil) to avoid chemical corrosion.
Process matching: If the vacuum oil immersion process is used, a low-porosity paper tube must be selected to prevent bubbles from remaining.
Cost balance: avoid choosing inferior materials at low prices, as long-term operating failures may lead to higher maintenance costs.

Summary

The purchase of wrinkled paper tubes for oil-immersed transformers should focus on the three cores of oil resistance, insulation strength, and mechanical stability. Combined with the transformer design parameters and operating environment, select products that have passed authoritative certification and have been verified in practice. It is recommended to conduct a small batch trial before purchasing to ensure that the performance matches the actual needs.

ZTelecGroup, a professional manufacturer of crepe paper tubes, was founded in 1958. For high-quality crepe paper tubes, please choose ZTelecGroup. Leave a message on the website to get free samples.