1, glass insulator excellent dielectric properties and no aging phenomenon
The insulation performance of the insulator is closely related to the internal molecular structure of the insulating material. Glass is an amorphous structure, is no fixed melting point of silicate compounds, dense structure, uniform texture, generated by the easy to control continuous production process to eliminate the production personnel on the insulator performance of the human influence. SiO2 is the skeleton of the glass, other oxides are filled in the skeleton, and are connected by chemical bonds, interaction is large, not easy to be polarized by the electric field, showing a good inertia, is an ideal insulation material.
2, glass insulator good mechanical properties and temperature difference characteristics
When the vitreous body is still in a high temperature state after pressing and forming, the surface of the vitreous body is cooled suddenly by spraying controlled cold air, so as to produce uniform prestress, so that the interior of the vitreous body shrinks due to cold and produces internal tension, which makes the vitreous surface appear a permanent compressive stress. After the glass body through the tempering process, its mechanical impact resistance has been greatly improved. In addition, when a single grounding short circuit occurs in the transmission line, a large short circuit current will be generated, which requires that the insulator has good arc resistance and that the tensile strength cannot be reduced. The arc resistance of tempered glass insulator is higher than that of porcelain insulator, but the tensile strength has not decreased significantly.
3, glass insulator "zero value" self-explosion and good residual tensile strength
This characteristic of "zero value" self-detonation is the most significant feature of tempered glass insulators over other insulators. Tempered glass insulators have no hidden defects, compared with porcelain insulators, as long as the glass body is intact, there is no need to test, which provides great convenience for the line inspection department to patrol the line and timely discovery. The glass insulator residuals still have good tensile strength after detonation. The electrical performance of the stump is equally reliable, even when there is too much electrical stress, such as flashover caused by overvoltage across the insulator string including the stump, the internal arc is stopped by the glass particles pressed tightly at the head of the stump, while the arc is completely outside. So it will not cause the line to drop the vicious accident. When the glass insulator is self-breaking, the broken glass on the ground is irregularly granular, with a particle diameter of about 10 mm. Due to the electrical equipment under the glass insulator string, the particles fall on the equipment, and the secondary scattering range is large, and the diameter can reach 3 to 4 m. Under the hanging frame of the glass insulator string, there are wave blockers, lightning arresters, isolation switches, coupling capacitors, including the main transformer and other electrical equipment, and the glass particles will not break the electrical equipment.
4, glass insulator long life and good electrical performance
The glass parts of the insulator are tempered (760 ~ 780℃) to obtain a uniform distribution of tempered internal stress, which is a permanent stress and will not decrease with the extension of the product running time. The maximum temperature when the line is running is 70 ~ 8O℃, which is much lower than the annealing temperature of the glass; In case of lightning or pollution flash, although the arc temperature can reach more than 3 000 ° C, the arc time is very short, and the glass cannot be annealed. Therefore, the glass insulator has a long life cycle and is not easy to aging characteristics are scientifically based. At the same time, the average breakdown strength of the tempered glass medium is up to 1 700 kV/cm, such as lightning burns the glass surface (depth 1 ~ 2 mm) without injury to the iron cap and steel foot, the product can continue to be used. When porcelain insulators burn porcelain glaze and synthetic mandrel, these two products must be replaced. Therefore, the electrical strength of the glass insulator is quite stable during the entire operation, and the electrical performance is not aging
