A lot of disk-shaped insulators are hung on one end of the high-voltage wire connection tower to increase the creepage distance, usually made of glass, ceramic or composite materials, called electricity insulators.
In order to prevent dust and other pollution from adhering to the surface of the insulator, a path is formed to be broken down by the voltage across the insulator, that is creepage. Therefore, increase the surface distance, that is the creeping distance, and the distance along the insulating surface that is the leakage distance is called the creeping distance. Climbing distance = surface distance / the highest voltage of the system. Depending on the degree of pollution, a crawl distance of 31 mm/kV is generally used in heavily polluted areas.
A zero-value insulator refers to an insulator whose potential distribution at both ends of the insulator is close to zero or equal to zero during operation.
The influence of zero or low value insulators: The insulation of overhead line conductors depends on the insulator string. Due to manufacturing defects or external effects, the insulation performance of the insulator will continue to deteriorate. When the insulation resistance decreases or becomes zero, it is called a low-value or zero-value insulator. We have tested the lines, and the proportion of zero or low-value insulators is as high as about 9%. This is another main reason for the high lightning strike rate of overhead lines. The insulator is smooth, which can reduce the capacitive reactance between the wires to reduce the current loss.
The main function of the insulator is to achieve electrical insulation and mechanical fixation. To this end, various electrical and mechanical performance requirements are stipulated.
For example, under the specified operating voltage, lightning overvoltage and internal overvoltage, there will be no breakdown or flashover along the surface.
Under the specified long-term and short-term mechanical load, no damage and damage will occur.
After long-term operation under specified mechanical and electrical loads and various environmental conditions, no significant deterioration will occur.
The fittings of the insulators do not produce obvious corona discharge under the operating voltage, so as not to interfere with the radio or television reception.
Because insulators are widely used devices, their connection fittings are also required to be interchangeable.
In addition, the technical standards of insulators also require various electrical, mechanical, physical, and environmental conditions to test their performance and quality according to different models and conditions of use.