Classification of insulation materials
Insulation materials include gas insulation materials, liquid insulation materials, and solid insulation materials. Involving various industries such as electrical engineering, petrochemicals, light industry, building materials, textiles, etc.
Gas insulation materials usually have good insulation performance in dry gases at room temperature and pressure. As a gas dielectric material for insulation, it also needs to meet the requirements of physical, chemical properties, and economic efficiency. Air and sulfur hexafluoride gas are commonly used gas insulation materials. Air has good insulation performance, and its insulation performance can be instantly and automatically restored after breakdown. Its electrical and physical properties are stable, with extremely rich sources and a wide range of applications. However, the breakdown voltage of air is relatively low, and factors such as sharp electrodes, close distances, steep voltage waveforms, high temperatures, and high humidity can all reduce the breakdown voltage of air. Compressed air or vacuum pumping methods are often used to increase the breakdown voltage of air. Sulfur hexafluoride (SF6) gas is a non flammable, non explosive, colorless and odorless inert gas. 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 and chemical stability, but at high temperatures above 600 ℃, sulfur hexafluoride gas will decompose and produce toxic substances. Therefore, the following aspects should be noted during use.
(1) Strictly control the moisture content and take dehumidification and moisture-proof measures.
(2) Use appropriate adsorbents to absorb harmful substances and moisture.
(3) The pressure of sulfur hexafluoride gas in the circuit breaker should not be too high to cause liquefaction.
(4) The place where sulfur hexafluoride equipment is placed should have good ventilation conditions.
(5) Necessary and reliable labor protection measures should be taken for operation and maintenance personnel.
Liquid insulation materials Figure 1: Insulating oil includes natural mineral oil, natural vegetable oil, and synthetic oil, as shown in Figure 1. Natural mineral oil is widely used. It is a neutral liquid obtained through different degrees of refining from petroleum crude oil, with a golden color and good chemical and electrical stability. Mainly used in power transformers, low oil circuit breakers, high-voltage cables, oil immersed capacitors and other equipment. Natural vegetable oils include castor oil, soybean oil, etc. Synthetic oils include oxidized benzyl silicone oil, benzyl silicone oil, etc., mainly used in power transformers, high-voltage cables, and oil immersed paper capacitors. Insulation oil can be contaminated and aged due to various factors during storage, transportation, and operation. Heat and oxygen play the most important role in the aging of oil. The measures taken in industry to prevent oil aging include: strengthening heat dissipation to reduce oil temperature; Use nitrogen and thin film to isolate transformer oil from air; Use desiccants to eliminate moisture; Add antioxidants; Prevent exposure to sunlight, etc. After oil is contaminated, pressure filtration or electric purification methods can be used for purification and regeneration. In order to ensure the safe operation of oil filled equipment, it is necessary to regularly check the temperature rise, oil surface height, oil flash point, acid value, breakdown strength, and tangent value of dielectric loss angle. If necessary, chromatographic analysis of transformer oil should also be carried out. When adding oil, try to use the original or similar model as much as possible, and conduct a mixing test.
There are many types of solid insulation materials, which have excellent insulation performance and are widely used in power systems. Common solid insulation materials include: insulation paint and insulation adhesive; Fiber products; Rubber, plastics and their products; Glass and ceramic products; Mica, asbestos and their products, etc. Insulating paint and adhesive are important insulation materials based on high polymer materials that can solidify into insulating hard films or insulating whole under certain conditions. Insulating paint is mainly composed of paint base, solvent, diluent, filler, and other parts. After the film is formed and cured, the insulation strength of insulating paint is high. It can generally be used as impregnation insulation or coating insulation for electric motors and electrical coils. It can be divided into impregnating paint, enameled wire paint, covering paint, silicon steel sheet paint, and anti corona paint according to their uses. Insulation adhesive is similar to insulation paint, usually with filler added, and is widely used for casting cable joints, sleeves, 220kV and below current transformers, and 10kV and below voltage transformers. The insulation adhesives used include yellow cable adhesive, black cable adhesive, epoxy cable adhesive, epoxy resin adhesive, epoxy polyester adhesive, etc. Insulating fiber products refer to insulation materials made from insulating paper, cardboard, paper tubes, and various fiber fabrics. Impregnated fiber products are made by using insulating fiber products as substrates and dipping them in insulating paint. They have certain mechanical strength, electrical strength, moisture resistance, as well as some special functions such as mold resistance, electricity resistance, and radiation resistance. Insulated electrical laminated products are layered insulation materials made from fibers as the substrate, coated with different adhesives, and hot pressed or rolled. Their performance depends on the substrate, adhesive and its forming process. They can be made into products with excellent electrical properties, mechanical properties, heat resistance, mold resistance, arc resistance, corona resistance, and other characteristics.
Gas insulation materials usually have good insulation performance in dry gases at room temperature and pressure. As a gas dielectric material for insulation, it also needs to meet the requirements of physical, chemical properties, and economic efficiency. Air and sulfur hexafluoride gas are commonly used gas insulation materials. Air has good insulation performance, and its insulation performance can be instantly and automatically restored after breakdown. Its electrical and physical properties are stable, with extremely rich sources and a wide range of applications. However, the breakdown voltage of air is relatively low, and factors such as sharp electrodes, close distances, steep voltage waveforms, high temperatures, and high humidity can all reduce the breakdown voltage of air. Compressed air or vacuum pumping methods are often used to increase the breakdown voltage of air. Sulfur hexafluoride (SF6) gas is a non flammable, non explosive, colorless and odorless inert gas. 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 and chemical stability, but at high temperatures above 600 ℃, sulfur hexafluoride gas will decompose and produce toxic substances. Therefore, the following aspects should be noted during use.
(1) Strictly control the moisture content and take dehumidification and moisture-proof measures.
(2) Use appropriate adsorbents to absorb harmful substances and moisture.
(3) The pressure of sulfur hexafluoride gas in the circuit breaker should not be too high to cause liquefaction.
(4) The place where sulfur hexafluoride equipment is placed should have good ventilation conditions.
(5) Necessary and reliable labor protection measures should be taken for operation and maintenance personnel.
Liquid insulation materials Figure 1: Insulating oil includes natural mineral oil, natural vegetable oil, and synthetic oil, as shown in Figure 1. Natural mineral oil is widely used. It is a neutral liquid obtained through different degrees of refining from petroleum crude oil, with a golden color and good chemical and electrical stability. Mainly used in power transformers, low oil circuit breakers, high-voltage cables, oil immersed capacitors and other equipment. Natural vegetable oils include castor oil, soybean oil, etc. Synthetic oils include oxidized benzyl silicone oil, benzyl silicone oil, etc., mainly used in power transformers, high-voltage cables, and oil immersed paper capacitors. Insulation oil can be contaminated and aged due to various factors during storage, transportation, and operation. Heat and oxygen play the most important role in the aging of oil. The measures taken in industry to prevent oil aging include: strengthening heat dissipation to reduce oil temperature; Use nitrogen and thin film to isolate transformer oil from air; Use desiccants to eliminate moisture; Add antioxidants; Prevent exposure to sunlight, etc. After oil is contaminated, pressure filtration or electric purification methods can be used for purification and regeneration. In order to ensure the safe operation of oil filled equipment, it is necessary to regularly check the temperature rise, oil surface height, oil flash point, acid value, breakdown strength, and tangent value of dielectric loss angle. If necessary, chromatographic analysis of transformer oil should also be carried out. When adding oil, try to use the original or similar model as much as possible, and conduct a mixing test.
There are many types of solid insulation materials, which have excellent insulation performance and are widely used in power systems. Common solid insulation materials include: insulation paint and insulation adhesive; Fiber products; Rubber, plastics and their products; Glass and ceramic products; Mica, asbestos and their products, etc. Insulating paint and adhesive are important insulation materials based on high polymer materials that can solidify into insulating hard films or insulating whole under certain conditions. Insulating paint is mainly composed of paint base, solvent, diluent, filler, and other parts. After the film is formed and cured, the insulation strength of insulating paint is high. It can generally be used as impregnation insulation or coating insulation for electric motors and electrical coils. It can be divided into impregnating paint, enameled wire paint, covering paint, silicon steel sheet paint, and anti corona paint according to their uses. Insulation adhesive is similar to insulation paint, usually with filler added, and is widely used for casting cable joints, sleeves, 220kV and below current transformers, and 10kV and below voltage transformers. The insulation adhesives used include yellow cable adhesive, black cable adhesive, epoxy cable adhesive, epoxy resin adhesive, epoxy polyester adhesive, etc. Insulating fiber products refer to insulation materials made from insulating paper, cardboard, paper tubes, and various fiber fabrics. Impregnated fiber products are made by using insulating fiber products as substrates and dipping them in insulating paint. They have certain mechanical strength, electrical strength, moisture resistance, as well as some special functions such as mold resistance, electricity resistance, and radiation resistance. Insulated electrical laminated products are layered insulation materials made from fibers as the substrate, coated with different adhesives, and hot pressed or rolled. Their performance depends on the substrate, adhesive and its forming process. They can be made into products with excellent electrical properties, mechanical properties, heat resistance, mold resistance, arc resistance, corona resistance, and other characteristics.
