Glass insulators have good basic properties and are widely used and popularized in different fields. The main basic properties include electrical, mechanical and thermal properties. In addition, it is also resistant to environmental and aging resistance. Different properties of glass insulators have different properties in different environments, so the main performance of glass insulators should be good. When the voltage level of glass insulator is increased, its size and weight are also increased, but the electrical and mechanical properties do not increase in proportion, and the performance of heat-resistant change decreases. Therefore, the glass insulator with high voltage level is more difficult to be manufactured. It is produced in accordance with a certain process in production to ensure the good performance of glass insulators.
(1) mechanical properties: glass insulators are often subjected to the action of gravity and tension, wind, icing weight, self weight of glass insulators, wire vibration, equipment operation mechanical force, short-circuit electric power, earthquake and other mechanical forces. The relevant standards of the state have strict requirements for mechanical properties. For the mechanical properties of glass insulators, it is necessary to ensure that glass insulators can bear the gravity and tension of the wire and bear different resistance, so that glass insulators are of good use value in different use.
Electrical performance: the destructive discharge along the insulation surface is called flashover. Flashover characteristics are the main electrical properties of glass insulators. For different voltage grades, the voltage requirements of glass insulators are different, and the indexes include the power frequency dry, the wet pressure resistance, the lightning impulse resistance pressure, the lightning impulse cut wave resistance, the operation impact resistance pressure and so on. To avoid breakdown during operation, the breakdown voltage of glass insulator is higher than that of flashover voltage. In the factory test, the breakdown type porcelain glass insulator usually passes through the spark test, that is, adding high pressure to make the insulation surface frequent spark, maintain a certain time and see if it is broken down. Some glass insulators also need corona test, radio interference test, partial discharge test and dielectric loss test. Glass insulators in high altitude areas decrease the electrical intensity because of the decrease of air density. Therefore, the tolerance voltage should be improved to the standard atmosphere. The flashover voltage of polluted glass insulator is much lower than that of its dry and wet flashover voltage. Therefore, the polluted area must be strengthened with insulation or pollution resistant glass insulators, and the ratio of creepage distance and rated voltage should be higher than that of the normal type. Compared with the AC glass insulators, the DC glass insulators have poor electric field distribution, the adsorption of pollution particles and the electrolysis, the low flashover voltage, which generally requires special structural design and greater creeping distance.
The thermal performance of glass insulator is required: outdoor temperature tolerance of the blast. For example, glass insulator requires several times of cold and heat circulation without cracking. Because of the current passing through the insulated bushing, the temperature rise of its components and insulation parts and the allowable short-time current value must comply with the relevant standards. In the use of glass insulation to pay attention to the good performance of the product, glass insulator temperature resistant ability to be good, do not in use, because the current too large impact glass insulators performance.
The above is the mechanical, electrical and thermal properties of glass insulators. In the use and production of glass insulation, it is necessary to pay attention to its good use characteristics, ensure its quality assurance and value, so that it has good product value in different use environment.