Classification of insulation materials

- Feb 01, 2019-

The insulating material includes a gas insulating material, a liquid insulating material, and a solid insulating material. Involved in electrical, petrochemical, light industry, building materials, textiles and many other industries.

Gas insulating material

Under normal circumstances, the dry gas at normal temperature and pressure has good insulation properties. As a gas dielectric material for an insulating material, it is also required to meet physical, chemical, and economic requirements. Air and sulfur hexafluoride gas are commonly used gas insulating materials.


Sulfur hexafluoride (SF6) gas is a kind of inert gas which is non-combustible, non-explosive, colorless and odorless. It has good insulation performance and arc-extinguishing ability, far higher than air, and has been widely used in high-voltage electrical appliances. Sulfur hexafluoride gas also has excellent thermal stability and chemical stability, but at a high temperature of 600 ° C or higher, sulfur hexafluoride gas will be decomposed and toxic substances will be produced. Therefore, the following aspects should be noted in use.

(1) Strictly control the water content and do dehumidification and moisture protection measures.

(2) Use appropriate adsorbents to absorb harmful substances and water.

(3) The pressure of sulphur hexafluoride gas in the circuit breaker should not be too high and liquefaction occurs.

(4) The place where the sulphur hexafluoride equipment is placed should have good ventilation conditions.

(5) It is necessary and reliable labor protection measures for the operation and maintenance personnel. 

Liquid insulation

Insulating oils are natural mineral oils, natural vegetable oils and synthetic oils as shown. Natural mineral oil is widely used. It is a neutral liquid obtained from petroleum crude oil after various degrees of refining and refining. It is golden yellow and has good chemical stability.

Sexual and electrical stability. Mainly used in power transformers, oil-less circuit breakers, high-voltage cables, oil-immersed capacitors and other equipment. Natural vegetable oils include castor oil, soybean oil and the like. Synthetic oils include oxidized biphenyl methyl silicone oil, benzyl silicone oil, etc., and are mainly used in power transformers, high voltage cables, and oil-impregnated paper capacitors.

Solid insulation

There are many types of solid insulating materials, and their insulating properties are excellent, and they are widely used in power systems. Commonly used solid insulating materials are: insulating varnish, insulating rubber; fiber products; rubber, plastic and its products; glass, ceramic products; mica, asbestos and its products.

Insulating varnish and insulating rubber are all important insulating materials based on high molecular polymer and can be cured into insulating hard film or insulating whole under certain conditions.

The insulating varnish is mainly composed of a lacquer base, a solvent, a diluent, a filler and the like. The insulating varnish has a high dielectric strength after being formed and cured, and can generally be used as an impregnating or coating insulating of a motor or an electrical coil. According to the use, it can be divided into impregnating varnish, enameled wire lacquer, covering lacquer, silicon steel lacquer and anti-corona lacquer.