A device that can withstand voltage and mechanical stress installed between conductors or conductors of different potentials and grounding members. There are many types of insulators with different shapes. Although the structure and appearance of different types of insulators are quite different, they are composed of two parts: insulators and connecting fittings.
Insulators are a special insulation control that can play an important role in overhead transmission lines. In the early years, insulators were mostly used for telegraph poles. Slowly, a lot of disk-shaped insulators were hung on one end of the high-voltage wire connection tower. It was used to increase the creepage distance, usually made of glass or ceramic, called insulator. Insulators should not fail due to various electromechanical stresses caused by changes in the environment and electrical load conditions, otherwise the insulators will not have a significant effect and will damage the use and operating life of the entire line.
Founded in 2010, Taporel Electrical (Jiangsu) Power Fitting Co., Ltd, held by Shaanxi Taporel Electrical Technology Co., Ltd. in Yangtze river delta economic belt, is a professional company specializing in R&D and manufacture of composite insulator fittings, power line fittings, and other fittings for transmission and distribution lines. It directly provides fittings for Taporel Electrical and Wishpower.
According to different installation methods, insulators can be divided into suspension insulators and post insulators; according to the different insulating materials used, they can be divided into porcelain insulators, glass insulators and composite insulators (also called composite insulators). according to different voltage levels, they can be divided into Low-voltage insulators and high-voltage insulators. according to the different environmental conditions used, the pollution-resistant insulators used in polluted areas are derived; according to the different types of voltages, DC insulators are derived. there are also various special-purpose insulators, such as insulating crossarms, Semiconductor glaze insulators and tension insulators for power distribution, spool insulators and wiring insulators, etc. In addition, according to the different breakdown possibilities of insulators, it can be divided into A-type, non-breakable insulators and B-type instant-breakable insulators.
Suspension insulators are widely used in insulation and mechanical fixing of high-voltage overhead transmission lines and soft busbars of power stations and substations. In the suspension insulator, it can be divided into disc suspension insulator and rod suspension insulator. Disc suspension insulators are the most widely used insulators for transmission lines. Rod suspension insulators have been widely used in Germany and other countries.
Post insulators are mainly used for insulation and mechanical fixing of bus bars and electrical equipment in power plants and substations. In addition, post insulators are often used as part of electrical equipment such as disconnect switches and circuit breakers. In post insulators, it can be divided into pin post insulators and rod post insulators. Pin post insulators are mostly used in low-voltage power distribution lines and communication lines, while rod post insulators are mostly used in high-voltage substations.
Porcelain insulator. Insulator is an insulator made of electrical ceramics. Electrical ceramics are baked from quartz, feldspar and clay as raw materials. The surface of the porcelain part of the porcelain insulator is usually covered with enamel to improve its mechanical strength, waterproof infiltration, and increase surface smoothness. Among all kinds of insulators, porcelain insulators are the most commonly used.
The glass insulator is an insulator made of tempered glass. The surface is in a state of compression and prestress. If cracks and electrical breakdown occur, the glass insulator will break into small pieces by itself, commonly known as "self-explosion". This feature makes it unnecessary for glass insulators to perform "zero value" detection during operation.
Composite insulators are also called composite insulators. The insulator consists of a glass fiber resin core rod (or core tube), a sheath of organic materials and an umbrella skirt. Its characteristics are small size, light weight, high tensile strength, and excellent anti-fouling flashover performance. But the anti-aging ability is not as good as porcelain and glass insulators. Composite insulators include: rod-shaped suspension insulators, insulating cross arms, post insulators and hollow insulators (namely composite bushings). Composite bushings can replace porcelain bushings used in a variety of power equipment, such as transformers, lightning arresters, circuit breakers, capacitive bushings and cable terminals. Compared with the porcelain sleeve, it not only has the advantages of high mechanical strength, light weight, and small dimensional tolerance, but also avoids damage caused by explosion.
Low-voltage insulators and high-voltage insulators Low-voltage insulators refer to insulators used for low-voltage power distribution lines and communication lines. High-voltage insulators refer to insulators used for high-voltage and ultra-high-voltage overhead transmission lines and substations. In order to meet the needs of different voltage levels, different numbers of single (piece) insulators of the same type are usually used to form insulator strings or multi-section insulation pillars.
Pollution-resistant insulators mainly take measures to increase or enlarge the umbrella skirt or umbrella edge of the insulator to increase the creepage distance of the insulator, so as to improve the electrical strength of the insulator in a dirty state. At the same time, the structure of the umbrella skirt is also changed to reduce the amount of natural pollution on the surface to improve the anti-pollution flashover performance of the insulator. The creepage ratio of pollution-resistant insulators is generally 20% to 30% higher than that of ordinary insulators, or even more. Pollution-resistant insulators with a double-layer umbrella structure are used in areas with frequent pollution flashovers in China's power grid. This type of insulator has strong self-cleaning ability and is easy to clean manually.
DC insulators mainly refer to disk insulators used in DC transmission. DC insulators generally have a longer creepage distance than AC pollution-resistant insulators, and their insulators have a higher volume resistivity (not less than 10Ω·m at 50°C), and their connecting fittings should be equipped with sacrifices to prevent electrolytic corrosion. Electrode (such as zinc sleeve, zinc ring).
Type A and Type B insulators Type A is non-breakdown insulator, and its dry flashover distance is not 3 times (casting resin type) or 2 times (other materials type): B type can be broken down. Type insulator, its breakdown distance is less than 1/3 (cast resin type) or 1/2 (other material type) of the dry flashover distance. The dry flashover distance of the insulator refers to the shortest distance through the air along the outer surface of the insulator; the breakdown distance refers to the shortest distance in the insulating material of the insulator.
The main function of insulators is to achieve electrical insulation and mechanical fixation, for which various electrical and mechanical performance requirements are specified. Such as under the specified operating voltage, lightning overvoltage and internal overvoltage, no breakdown or flashover along the surface; under the specified long-term and short-term mechanical load, no damage or damage; under the specified machine , After long-term operation under electric load and various environmental conditions, no obvious deterioration will occur; the fittings of insulators will not produce obvious corona discharge under the operating voltage, so as not to interfere with radio or television reception. Because insulators are widely used devices, their connection fittings are also required to be interchangeable. In addition, the technical standards of insulators also require various electrical, mechanical, physical, and environmental conditions to test the performance and quality of the insulators according to different types and conditions of use.
In humid weather, the dirty insulator is prone to flashover discharge, so it must be cleaned up to restore the original insulation level. The general area is cleaned once a year, and the dirty area is cleaned twice a year (once before the foggy season).
Power cut cleaning means that workers climb the pole and wipe with a rag after the line is cut off. If it is not clean, you can wipe it with a damp cloth or detergent. If it is still not clean, you should replace the insulator or replace the synthetic insulator.
Generally, an insulating rod equipped with a brush or tied with cotton yarn is used to wipe the insulator on the running line. The electrical performance and effective length of the insulating rod used, as well as the distance between the person and the live part, shall comply with the regulations of the corresponding voltage level, and special personnel must be supervised during operation.
There are two methods: big water flushing and small water flushing. The flushing water, the effective length of the operating rod, the distance between the person and the live part, etc. must meet the requirements of the industry regulations.