Due to the high mechanical strength of the surface layer of the tempered glass insulator, cracks are less likely to occur on the surface. The electrical strength of the glass generally remains constant throughout the operation, and its aging process is much slower than that of porcelain. Therefore, the glass insulator is mainly scrapped due to self-damage, which occurs during the first year of operation, but the defects of the porcelain insulator are only in operation. It was only discovered after the year.
The creepage distance, structure and material of the pin insulator are closely related to the flashover voltage. Under normal circumstances, the flashover voltage increases with the increase of the creepage distance. The structural shape of the insulator directly affects the antifouling performance of the insulator, and the reasonable structural design has a smooth surface, is not easy to form eddy currents, and has a small amount of accumulated dirt, thereby increasing the flashover voltage. The polymer organic composite material is used because of its large shape coefficient, large surface resistance and good water repellency, and good antifouling performance. Therefore, in the selection of insulators, the geometric creepage and structure must be reasonably selected according to the specific conditions, and new composite technology is used to actively promote the use of composite insulators.
The glass insulator insulator is an insulator made of tempered glass. The surface is in a state of compressive prestressing. If cracks and electrical breakdown occur, the glass insulator will break into small pieces by itself, commonly known as "self-explosion." This feature eliminates the need for "zero value" detection of the glass insulator during operation.
Since some enhancers are located upstream of the promoter and some are downstream, the effect of the insulator does not depend on the relative position of the insulator to the promoter. Therefore, the reason for the directionality of the insulator effect has not really been clarified. It has now been found that two loci affect the function of the insulator in a transactivation manner. The white identification insulator encoded by the gene S2J (Hw) has an insulating effect only after it is combined with the insulator. When the gene was mutated, although an insulator was inserted into the y locus, the insulation was lost and y was expressed in all tissues. Another locus is mod (mdg 4). After mutation, the effect of this gene is opposite to that of Su(Hw), that is, these mutants enhance the insulation and expand the insulation effect of the insulator without directionality. That is, blocking the effects of enhancers on both the upstream and downstream sides. There is an explanation that the first is Su (Hw) combined with the insulator DNA, so that the insulator has an insulating effect. Mod(mdg4) is combined with Su(Hw) to lose the insulation effect of the insulator; the mutated mod(mdg4) cannot be combined with Su(Hw), so the insulator enhances the insulation.
A few hundred nucleotide pairs in length are a regulatory sequence usually located between a promoter and a positive regulatory element (enhancer) or a negative regulator (which is heterochromatin). The insulator itself has neither a positive effect nor a negative effect on the expression of the gene, and its function is simply to prevent other regulatory elements from acting on the activation or inactivation effects of the gene.