In transformers, in addition to the primary and secondary coils, there are several other important components and accessories. The insulating material is one of the most critical components of a transformer. Sufficient insulation between different active parts of the transformer is necessary for its safe operation. Adequate insulation is not only necessary to isolate coils from one another, or from the core and tank, but also ensures the safety of the transformer against accidental over voltages.

The solid insulation materials widely used in the transformer are

1. Electrical grade paper, kraft paper
2. Pressboard,diamond paper

These are cellulose based paper which is widely used for conductor insulation in oil filled transformers. There are various grades of cellulose paper such as:

Kraft paper:

Thermal class E (120º) as per IEC 554-3-5 in thickness from 50 to 125 microns.

Thermally Upgraded paper Thermal class E (120°) as per IEC 554-3-5 in thickness from 50 to 125 microns.

Diamond dotted Epoxy paper in various thicknesses. This improve thermal properties as compared to normal Kraft paper.

       3. Wood and insulated wood

Electrical laminated wood is widely used as insulation and supporting materials in transformers and instrument transformers. It has many virtues such as moderate specific gravity, high mechanical properties, easy vacuum drying, no bad inner-reaction with transformer oil, easy mechanical processing, etc. The dielectric constant of this material is close to transformer oil, so it makes a reasonable insulation match. And it can be used in the transformer oil of 105℃ for a long time.

People usually use this material to make upper/lower pressure pieces, cable supporting beams, limbs, spacer blocks in oil-immersed transformers, and clamps in instrument transformers. It replaced steel plates, insulating paper sheets, epoxy paper sheets, epoxide woven glass fabric lamination in these fields, and cut down the material expenses and weight of transformers.

      4. Insulating tape

Electrical tape (or insulating tape) is a type of pressure-sensitive tape used to insulate electrical wires and other materials that conduct electricity. It can be made of many plastics, but PVC (polyvinyl chloride, “vinyl”) is most popular, as it stretches well and gives an effective and long lasting insulation. Electrical tape for class H insulation is made of fiberglass cloth.

We, TRIHOPE has supplied large quantity kraft paper, presspan paper, diamond paper, densified wood and insulation tape to overseas customers, including Mexico, South Africa, Pakistan etc. Most welcome you send inquiries to our company.

Oil is an equally important part of a transformer’s overall insulation. Oil,The main function of insulating oil in a transformer is to provide electrical insulation between the various energized parts; it also acts as a protective coating layer to prevent oxidation of the metal surfaces.Another important function of the oil is to enhance heat dissipation. Transformer cores and windings get heated up during operation due to various power losses. Oil takes heat away from the core and windings by the process of conduction and carries heat to the surrounding tank, which is then radiated out to the atmosphere.