What is a composite suspension insulator?
Composite suspension insulators are composed of iron caps, porcelain bushing fittings (suspension or silicone rubber) and steel feet (guide rods), and are cemented together. All adopt the internationally advanced cylindrical head structure, which has the characteristics of small head size. Light weight, high strength, large creepage distance. It can save metal materials and reduce production line costs. In order to meet the needs of live work, the brim of the hat adopts the traditional household structure shape. Composite insulator products are used to insulate and suspend conductors in HV and EHV AC and DC transmission lines. In the early years, insulators were mostly used on utility poles (low voltage), and gradually developed into many disc or column insulators hanging on one end of the high voltage wire connection tower, usually made of glass, ceramic or silicone rubber to increase the creepage distance. They are called insulators.
Composite suspension insulators have zero-value self-breaking characteristics. As long as it is observed on the ground or on the helicopter, there is no need to board the pole to inspect one by one, which reduces the labor intensity of workers. The annual self-breakage rate of products imported from the production line is 0.02-0.04%, which can save the maintenance cost of the production line. Good arc resistance and vibration resistance. The new surface of glass insulators that have been burned by lightning during operation remains a smooth glass body with a tempered internal stress protection layer. Therefore, it still maintains sufficient insulation and mechanical strength. Galloping disasters caused by icing conductors have occurred many times on 500 kV lines. After testing, the mechanical and electrical properties of composite suspension insulators that withstand conductor galloping have not declined. According to general reports from the power department, glass insulators are not easy to accumulate dirt and are easy to clean, and the glass insulators running on the southern line are cleaned after rain.
Composite suspension insulator
The mechanical and electrical properties of glass insulators on typical regional lines are regularly sampled and tested after operation. The accumulation of thousands of items of data shows that the mechanical and electrical properties of glass insulators after 35 years of operation are basically the same as when they left the factory, and there is no aging phenomenon. The main capacitance is large, the string voltage is evenly distributed, and the dielectric constant of the glass is 7-8, so that the composite insulator has a large main capacitance, and the string voltage is evenly distributed, which is beneficial to reduce the voltage on the insulator near the conductor side and the grounding side, thereby reducing radio interference, reduces corona losses, and prolongs the life of glass insulators. Operational practice has proved this point.
Composite suspension insulator
Some intensifiers are located upstream of the starter and some are located downstream, so the effect of the insulator does not depend on the relative position of the insulator and starter. Therefore, the reason for the directivity of the insulator effect is not very clear. Two sites have been found to affect the function of the insulator by counteracting. The protein encoded by the gene S2J(Hw) recognizes insulators, which only become insulating when bound to them. When a genetic mutation occurs, although the y locus is insulated, the insulation is lost and y is expressed in all tissues. Another site is mod(mdg4). After the gene is mutated, its effect is just opposite to that of Su(Hw), that is, these mutants enhance the insulating effect, so that the insulating effect of the insulator is no longer oriented and expanded, that is, the effects of the enhancers on both upstream and downstream sides are blocked . One explanation is that Su(Hw) first combines with the DNA of the insulator to make the insulator have an insulating effect. Mod(mdg4) combines with Su(Hw), making the insulator lose its insulating effect; mutant mod(mdg4) cannot combine with Su(Hw), so the insulator enhances the insulating effect.