Thermally Upgrade Transformer Insulation Paper

Thermally Upgrade Transformer Insulation Paper

Thermally Upgraded Transformer Insulation Paper

Thermally upgraded transformer insulation paper (Class 120) is a chemically modified cellulose insulating material engineered for oil-immersed distribution and power transformers. Unlike standard insulation kraft paper, this specialized paper undergoes a precise chemical treatment (typically using nitrogen-rich compounds like amine or cyanoethylation) to neutralize the acidic byproducts formed during thermal aging.

This chemical upgrade significantly retards the degradation rate of the cellulose fibers. By maintaining its mechanical DP (Degree of Polymerization) value under extreme conditions, thermally upgraded kraft paper allows transformers to safely operate at a continuous hotspot temperature of 120°C instead of the traditional 105°C limit, effectively extending the equipment's operational lifespan.

Technical Specifications & Parameters

Chengrui thermally upgraded insulation paper complies strictly with ASTM D2865  and IEC 60554 testing standards, ensuring premium dielectric purity and chemical uniformity.

• Base Material Composition: 100% Sulfate Wood Pulp

• Nitrogen Content ≥ 1.8%

• Thickness Range: 0.05mm, 0.075mm, 0.08mm, 0.125mm (Customizable)

• Moisture Content： 6.0% - 8.0%

Advantages of Thermally Upgraded Paper

1. Extended Polymerization Retention: It preserves its mechanical tensile strength up to 4 times longer than standard kraft paper when exposed to continuous 120°C oil temperatures.

2. Enhanced Overload Capacity: By raising the thermal limit to 120°C, it allows transformers to handle peak-load surges without triggering rapid insulation breakdown or gas generation.

3. High Transformer Oil Synergy: Chemically neutral and fully compatible with mineral oils and natural/synthetic ester fluids, ensuring low dielectric loss.

Applications in Heavy Electrical Power Grids

Where is thermally upgraded kraft paper  utilized?

High-Voltage Power Transformers: Layer-to-layer and conductor wrapping insulation to withstand extreme localized hotspot temperatures.

Step-Up/Step-Down Distribution Transformers: Enabling compact pole-mounted and pad-mounted transformer designs with higher power ratings.

Traction & Wind Power Transformers: Ideal for grid systems subject to frequent, drastic load fluctuations and thermal cycling.

Frequently Asked Questions

Q1: What is the precise definition of "thermally upgraded" paper?

A: It refers to cellulose paper that has been chemically treated with nitrogenous agents to contain at least 2%~2.4% nitrogen. This modification directly neutralizes moisture and organic acids, preventing early cellulose molecular chain breakage.

Q2: What is the difference between standard kraft paper and thermally upgraded paper?

A: Standard kraft paper has a continuous thermal limit of 105°C. Thermally upgraded paper increases this thermal rating to 120°C (Class 120 insulation), providing excellent thermal stability, less gas evolution, and prolonged mechanical elasticity under high heat.

Q3: Does Chengrui supply thermally upgraded paper in slit tapes or corrugated form?

Yes. We support full mechanical customizing. We supply this material in master rolls, precise narrow slit tapes (down to 10mm) for automated high-speed conductor wrapping, or converted into insulation components according to your schematics.