Disc difference voltage levels and insulators

    Used to support the live conductors and insulate electrical components. Usually installed from an insulating member (such as porcelain) and metal accessories (such as steel foot, iron caps, flange, etc.) with an adhesive glue or mechanical card machine surrogacy. Insulators in electrical power system application is very wide, it is generally outside the insulation, work under atmospheric conditions. External charged conductor overhead transmission lines, power plants and substations buses and a variety of electrical equipment shall be used to support insulators, aligning them with the earth (or ground thereof) or other potential difference of the conductor insulation.

    Categories insulator is usually divided into type and can not be breakdown breakdown type. By application is divided into line insulators and power plants, electrical insulators. Commonly used insulators basic form shown in Figure. Wherein the breakdown insulators for lines with male, butterfly, pin type, non-punch-through type have cross arms and Rod. Can breakdown insulators used in power plants, electrical with male pillar, hollow pillar and sleeve breakdown should not have rod-type porcelain pillar and container.

    Basic performance properties of the insulator including electrical, mechanical and thermal properties. In addition, there are anti-environment and anti-aging properties. When the insulator voltage rating, its size and weight also increased, but the electrical and mechanical properties are not scaled up, the heat blast performance. Therefore, the voltage level of high insulator is difficult to manufacture.

    ① electrical properties: the credit card of damage occurred along the insulation surface discharge called a flashover, flashover characteristics are the main electrical properties of the insulator. For different voltage levels, withstand voltage requirements vary insulator, which refers to the owner of the list marked with the frequency of dry, wet withstand voltage, lightning impulse withstand voltage, lightning impulse chopped wave voltage, switching impulse withstand voltage and the like. In order to avoid a breakdown in the operation, higher than the breakdown voltage insulator flashover voltage. In the factory test, can breakdown type of porcelain insulators usually after the spark test, namely a high voltage insulation surface occurs frequently spark, to maintain a certain time to see if the breakdown. Some insulators needed corona test, radio interference test, partial discharge test and dielectric loss test. High altitude insulators, due to air density decreases leaving the electrical strength decreases, and therefore its withstand voltage is converted to the standard atmospheric conditions should be increased accordingly. Contamination flashover voltage insulator when wet is much lower than its dry, wet flashover voltage, therefore, dirty areas must use reinforced insulation or Fog type insulators, which creepage distance (creepage distance and the ratio of the rated voltage) should be more Normal High. Compared with AC DC Insulator insulators, electric field distribution is poor, there are dirt particles and adsorption electrolysis, flashover voltage is low, generally require a special design and larger creepage distance.

    ② mechanical properties: Insulators often run by gravity and tension wires, wind, icing weight, weight insulators, wire vibration effects, equipment operating mechanical force, short-circuit power, earthquakes and other mechanical forces. There are strict requirements relating to standards for mechanical performance regulations.

    ③ thermal performance: outdoor insulators requires the ability to withstand rapid temperature change. Such as porcelain insulators requirements after several thermal cycling without cracking. Bushings because there is a current, temperature and insulating member of its parts and to allow short-time current value shall comply with the relevant standards.