Black Semi-Conductive Crepe Paper: Guide&Applications

Black Semi-Conductive Crepe Paper Black Semi-Conductive Crepe Paper is a specialized electrical insulating and shiel...

Black Semi-Conductive Crepe Paper

Black Semi-Conductive Crepe Paper is a specialized electrical insulating and shielding material designed for high-voltage power equipment and cable manufacturing. Combining specific semi-conductive shielding properties with excellent physical elasticity, it plays a critical role in eliminating localized partial discharges and uniforming electrical fields in the power industry.

Black Crepe Paper Material Overview

Black semi-conductive crepe paper is manufactured using 100% high-purity unbleached sulfate coniferous wood pulp paper (cable paper) as the base material. It is processed through impregnation or surface coating with high-molecular semi-conductive materials and then mechanically creped.

Material Property: It belongs to the class of semi-conductive materials, with a volume resistivity falling precisely between conductors and insulators.

Physical Appearance: It features a continuous, regular, black wrinkled texture on its surface. The edges are neatly slit without burrs, and the paper is completely free of any loose metallic conductive particles.

Compatibility: It has high oil absorption capacity and demonstrates outstanding chemical compatibility with transformer oil, silicone oil, mineral oil, and insulation vapor-phase drying systems (such as 140°C kerosene vapor-phase drying). It will not delaminate under high temperatures.

Black Crepe Paper Core Applications

The primary purposes of this material are electrical field voltage equalization and partial discharge prevention. It stops insulation breakdown caused by localized sharp-edge/tip discharges inside high-voltage electrical equipment:

Transformers and Instrument Transformers: It is used for wrapping the windings, coil lead positions, and condenser bushings’ outer screens of high-voltage/ultra-high-voltage current and voltage transformers to balance the internal electric field distribution.

High-Voltage Cable Joints and Terminations: It wraps around the transition zones between the conductor shield layer and the insulation shield layer of power cables, serving to maintain continuous shielding and lead out leakage currents.

Irregularly Shaped Electrical Components: Utilizing its high elasticity, it tightly wraps around sharp-angled or complex-shaped metallic components without leaving gaps, thereby eliminating tip discharge effects.

Black Crepe Paper Selection Guide

When purchasing or designing for engineering projects, four core indicators must be evaluated based on the equipment’s technical parameters and installation processes:

3.1 Electrical Parameter Selection (Volume Resistivity)

Principle: Choose the corresponding resistance class according to the specific voltage level (e.g., 10kV, 110kV, 500kV) and shielding requirements.

Caution: The semi-conductive resistivity must remain highly uniform. The surface must be dense without pinholes or impurities; otherwise, localized electrical field distortion will occur under high voltages.

3.2 Thickness and Basis Weight (Base Paper Specifications)

Common Base Paper Thicknesses: Typically available in 0.05 mm, 0.08 mm, 0.13 mm, and other variations.

Principle: Thinner paper (0.05 mm) is ideal for fine, multi-layered wrapping on coils where space is tightly constrained. Thicker paper (0.13 mm or above) offers higher mechanical strength and is suitable for machine wrapping that subjects the paper to higher tension.

3.3 Crepe Rate and Tensile Elongation

Principle: The crepe rate directly determines the elongation capacity of the paper (usually ranging from 30% to over 100%).

Application: For components with complex surfaces (such as bends or irregular stepped joints), models with a higher crepe rate and superior flexibility must be chosen to ensure a tight fit and prevent internal air gaps during wrapping.

3.4 Slitting Width (Installation Dimensions)

Standard Slitting Widths: 20 mm, 25 mm, 30 mm, 40 mm (while the master roll width generally ranges from 550 mm to 1100 mm).
Principle:
Manual Operation / Small Pipe Diameters: Opt for a 20 mm or 25 mm narrow tape for flexible wrapping.
Automatic Winding Machines / Large Diameters:Opt for 30 mm, 40 mm, or wider specifications to significantly boost construction efficiency.

Manufacturer Inquiry:

Xujue Electrical, your professional manufacturer of specialized transformer crepe paper. Fully compliant with IEC standards, we provide custom manufacturing and precision slitting to meet your exact specifications for insulating crepe paper. Free test samples and comprehensive technical solutions are available upon request.