Description
SIDA’s G4 Transformerboard High Density represents the pinnacle of cellulosic insulation technology, specifically designed for the most demanding transformer applications. With an apparent density of 1.0-1.3 g/cm³, this high-density board provides unmatched dimensional stability under mechanical stress and thermal cycling.
Manufacturing Excellence
Our G4 grade pressboard undergoes a specialized manufacturing process involving high-pressure processing of refined sulfate wood pulp, ensuring uniform fiber orientation and eliminating additional sizing or fillers. The result is a hard, dimensionally stable material with fiber-free surfaces that maintains structural integrity even under extreme electrical and mechanical stresses.
Our G4 grade pressboard undergoes a specialized manufacturing process involving high-pressure processing of refined sulfate wood pulp, ensuring uniform fiber orientation and eliminating additional sizing or fillers. The result is a hard, dimensionally stable material with fiber-free surfaces that maintains structural integrity even under extreme electrical and mechanical stresses.
Uncompromising Quality
Each board is manufactured under strict quality control to guarantee:
Each board is manufactured under strict quality control to guarantee:
-
Chemical Purity: High chemical purity ensures compatibility with transformer oils and prevents contamination
-
Mechanical Robustness: High compressive strength maintains oil duct geometry under electromagnetic forces and short-circuit conditions
-
Optimal Oil Impregnation: Excellent oil absorption (>10%) enhances dielectric strength and thermal conductivity
-
Thermal Class A (105°C): Stable performance at continuous operating temperatures up to 105°C per IEC 60085
The material is specifically engineered for transformers rated 110kV to 750kV and above, where failure is not an option.
Technical Data Sheet
| Test Report | ||||||
| Description of Products: G4 UHV Pressboard Board Thickness:6 mm Produces time:2024.5 | ||||||
| No. | Property | Unit | Normal Value | Test Result | Test Method | |
| 1 | Tolerance of Thickness | % | ≤5 | +2.5 | JB/T10443.2/ IEC60641-3-1: 2008 |
|
| 2 | Apparent Density | g/cm3 | 1.15-1.35 | 1.23 | ||
| 3 | Flexural strength | MD | MPa | ≥110 | 120.3 | |
| CMD | ≥90 | 112.4 | ||||
| 4 | Shrinkage after drying | MD | % | ≤0.4 | 0.21 | |
| CMD | ≤0.6 | 0.27 | ||||
| Thick.D | ≤4.0 | 2.3 | ||||
| 5 | Compressibility C | % | ≤3 | 2.9 | ||
| 6 | Reversible part of Compressibility Crev. | % | ≥70 | 72 | ||
| 7 | Oil absorption | % | ≥5.0 | 9.98 | ||
| 8 | PH of aqueous extract | / | 5.0-8.0 | 6.72 | ||
| 9 | Conductivity of aqueous extract | mS/m | ≤10 | 4.11 | ||
| 10 | Electrical strength (in oil) | KV/mm | ≥8 | 8.56 | ||
| 11 | Inner Layer Strength | MPa | ≥90 | 96.2 | ||
| 12 | Moisture content | % | ≤5.0 | 3.5 | ||
| Test result: Pass | ||||||
| Test Report | ||||||
| Description of Products: G4 UHV Pressboard Board Thickness:10 mm Produces time:2026.1 | ||||||
| No. | Property | Unit | Normal Value | Test Result | Test Method | |
| 1 | Tolerance of Thickness | % | ≤5 | +2.3 | JB/T10443.2/ IEC60641-3-1: 2008 |
|
| 2 | Apparent Density | g/cm3 | 1.15-1.35 | 1.25 | ||
| 3 | Flexural strength | MD | MPa | ≥110 | 121.4 | |
| CMD | ≥90 | 111.2 | ||||
| 4 | Shrinkage after drying | MD | % | ≤0.4 | 0.21 | |
| CMD | ≤0.6 | 0.26 | ||||
| Thick.D | ≤4.0 | 2.2 | ||||
| 5 | Compressibility C | % | ≤3 | 2.8 | ||
| 6 | Reversible part of Compressibility Crev. | % | ≥70 | 77 | ||
| 7 | Oil absorption | % | ≥5.0 | 9.93 | ||
| 8 | PH of aqueous extract | / | 5.0-8.0 | 6.74 | ||
| 9 | Conductivity of aqueous extract | mS/m | ≤10 | 4.17 | ||
| 10 | Electrical strength (in oil) | KV/mm | ≥8 | 8.73 | ||
| 11 | Inner Layer Strength | MPa | ≥90 | 98.2 | ||
| 12 | Moisture content | % | ≤5.0 | 3.6 | ||
| Test result: Pass | ||||||
Note:The product specifications provided are for reference purposes only. Please refer to the actual product for final specifications. We also offer various sizes and thicknesses to meet your specific needs. For further customization, please contact us.
Application Scenarios
1. Ultra-High Voltage Power Transformers
Voltage Class: 220kV – 750kV+
Components: Spacers, cylinders, press rings, support plates
Benefits: Withstands extreme electrical stresses while maintaining oil duct geometry for optimal cooling
Components: Spacers, cylinders, press rings, support plates
Benefits: Withstands extreme electrical stresses while maintaining oil duct geometry for optimal cooling
2. Distribution Transformers (High-Performance)
Voltage Class: 35kV – 110kV
Components: Winding spacers, insulation barriers, lead supports
Benefits: Enhanced short-circuit strength and thermal stability
Components: Winding spacers, insulation barriers, lead supports
Benefits: Enhanced short-circuit strength and thermal stability
3. Instrument & Traction Transformers
Components: Precision-machined insulation components
Benefits: Dimensional stability ensures consistent electrical clearances and performance
Benefits: Dimensional stability ensures consistent electrical clearances and performance
4. Oil Duct Strips & Spacers
Configuration: Rectangular strips, T-strips, trapezoidal profiles
Function: Creates cooling oil channels in layer and strip windings
Advantage: 30%+ higher compressive strength than traditional corrugated pressboard
Function: Creates cooling oil channels in layer and strip windings
Advantage: 30%+ higher compressive strength than traditional corrugated pressboard
5. Molded Insulation Components
Applications: Angle rings, sector rings, end rings
Process: Can be machined, punched, or molded into complex shapes
Result: Uniform dielectric field distribution in high-stress regions
Process: Can be machined, punched, or molded into complex shapes
Result: Uniform dielectric field distribution in high-stress regions
Frequently Asked Questions (FAQs)
Q1: What distinguishes G4 grade from other transformerboard grades?
A: G4 is a high-density grade (1.0-1.3 g/cm³) conforming to IEC 60641-3-1 Type B 3.1A, offering the highest mechanical and electrical strength for EHV/UHV applications. Standard grades typically have lower density (0.9-1.1 g/cm³) and are suitable for lower voltage classes.
A: G4 is a high-density grade (1.0-1.3 g/cm³) conforming to IEC 60641-3-1 Type B 3.1A, offering the highest mechanical and electrical strength for EHV/UHV applications. Standard grades typically have lower density (0.9-1.1 g/cm³) and are suitable for lower voltage classes.
Q2: How does oil impregnation improve performance?
A: The board’s porous cellulose structure absorbs 10-12% transformer oil, which: (1) displaces moisture, (2) increases dielectric strength by 2-3x, (3) improves thermal conductivity, and (4) enhances partial discharge resistance.
A: The board’s porous cellulose structure absorbs 10-12% transformer oil, which: (1) displaces moisture, (2) increases dielectric strength by 2-3x, (3) improves thermal conductivity, and (4) enhances partial discharge resistance.
Q3: Can SIDA G4 board be customized in thickness and dimensions?
A: Yes. Standard thickness: 0.5-10.0mm, with custom capabilities up to 30mm. Sheet sizes: 1000×2000mm, 2000×4000mm, or customized dimensions per your technical drawings.
A: Yes. Standard thickness: 0.5-10.0mm, with custom capabilities up to 30mm. Sheet sizes: 1000×2000mm, 2000×4000mm, or customized dimensions per your technical drawings.
Q4: What is the typical lead time?
A: 3-7 days for stocked items; 10-30 days for production orders depending on quantity and customization requirements.
A: 3-7 days for stocked items; 10-30 days for production orders depending on quantity and customization requirements.
Q5: How do you ensure batch-to-batch consistency?
A: We maintain retained samples from each production lot and implement Statistical Process Control (SPC) throughout the manufacturing process. All batches are tested per IEC 60641-3-1 before shipment.
A: We maintain retained samples from each production lot and implement Statistical Process Control (SPC) throughout the manufacturing process. All batches are tested per IEC 60641-3-1 before shipment.
Q6: Is G4 board suitable for dry-type transformers?
A: While optimized for oil-immersed transformers, G4 can be used in dry-type applications with proper treatment. For high-temperature dry-type transformers (>155°C), we recommend aramid-based insulation boards.
A: While optimized for oil-immersed transformers, G4 can be used in dry-type applications with proper treatment. For high-temperature dry-type transformers (>155°C), we recommend aramid-based insulation boards.
Q7: What storage conditions are recommended?
A: Store in dry, ventilated areas at 20±5°C and ≤65% relative humidity. Avoid direct sunlight and contact with moisture. Original packaging provides optimal protection.
A: Store in dry, ventilated areas at 20±5°C and ≤65% relative humidity. Avoid direct sunlight and contact with moisture. Original packaging provides optimal protection.
Quality Assurance & Testing Protocols
In-Process Testing
-
Moisture Content: Monitored continuously during production (target: 4-9%)
-
Thickness Variation: Laser gauging with ±2μm precision
-
Density Uniformity: Gamma-ray absorption scanning
Final Product Certification
Each batch undergoes comprehensive testing per IEC 60641-3-1:
-
Mechanical Testing: Tensile strength (MD/CMD), elongation, edge tear resistance
-
Electrical Testing: Dielectric strength in air and oil (50Hz AC)
-
Chemical Testing: Ash content, pH, conductivity, oil absorption
-
Dimensional Testing: Shrinkage after drying at 105°C
Third-Party Validation
-
ISO 9001:2015 Quality Management System
-
ROHS Directive 2011/65/EU compliance
-
IEC 60641-3-1 Type B 3.1A certificate of conformity