The seven common electrical insulation materials in transformers

1. Transformer oil

Transformer oil is one of the most common insulation materials in transformers. It has the dual tasks of insulation and heat dissipation. Transformer oil has excellent electrical insulation performance, and its compressive strength is much higher than that of air. Therefore, it can effectively isolate high and low voltage windings and prevent current leakage and short circuit. In addition, transformer oil also has good heat dissipation performance, which can effectively dissipate the heat generated inside the transformer, thereby maintaining the stable operation of the transformer. At the same time, transformer oil also has a certain anti-corrosion effect, which can protect the metal parts inside the transformer from corrosion.

2. Insulation sheets

Insulation sheet is another important insulating material in transformers. It is mainly used to make various insulating parts, such as soft paper tubes, stays, pads, phase partitions, iron yoke insulation, support insulation and corner rings. Insulation sheet is made of high-quality kraft wood pulp paper and has good electrical properties and mechanical strength after special processing. It can withstand high electric field strength and has certain tear and wear resistance, so it is an indispensable insulating material in transformers.

3. Cable paper

Cable paper is mainly used for inter-turn insulation, inter-layer insulation, lead insulation and reinforced insulation of end leads of transformer windings. Cable paper has different thicknesses and models to meet different insulation needs. It is usually made of high-quality cotton pulp or wood pulp, and has excellent electrical properties and mechanical strength after special process treatment. Cable paper can effectively isolate the current between windings, prevent the occurrence of short circuit and arc discharge, and thus ensure the safe operation of the transformer.

4. Adhesive tape products

Adhesive tape products are another common insulating material in transformers. They are mainly used for insulation between transformer windings and cores, between windings, and for insulation of iron yoke screws and tap changers. Adhesive tape products are made of adhesive tape coated with phenolic resin on one side, rolled into a cylinder or tube, and then baked and painted. It has good electrical properties and mechanical strength, and can withstand high electric field strength and mechanical stress. In addition, adhesive tape products also have certain moisture-proof and mildew-proof properties, and can maintain stable insulation properties in harsh environments.

5. Insulating wood

Insulating wood is mainly used as lead brackets, tap brackets, and wood screws in transformers. Commonly used insulating woods include ash, birch, etc. These woods need to be specially treated before use to improve their electrical properties and mechanical strength. Insulating wood can withstand a certain electric field strength and mechanical stress, and has good moisture and mildew resistance. In transformers, insulating wood can effectively support and fix various insulating components to ensure the stable operation of the transformer.

6. Varnished cloth

Varnished cloth (varnished tape) has good electrical properties and high strength and elasticity, so it is often used to wrap the bends of transformer leads or in places where high binding quality is required. Varnished cloth (varnished tape) is made of fiber materials (such as cotton cloth, silk cloth, etc.) impregnated with insulating varnish. After drying and curing, it has excellent electrical properties and mechanical strength. It can effectively isolate current, prevent short circuits and arc discharges, and can withstand certain mechanical stress and temperature changes.

7. Insulators

Insulators are mainly used as external insulation for transformer bushings. Insulators are made of natural mineral raw materials such as kaolin, quartz, and feldspar through molding, firing, and other processes, and have good electrical properties and mechanical strength. They can withstand high electric field strength and mechanical stress, and have good moisture and anti-fouling properties. In transformers, insulators can effectively isolate the current between the bushing and the external environment, prevent short circuits and arc discharges, and ensure the safe operation of the transformer.