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Product Structure and Type of Line Insulator

Pulished on Sep. 07, 2020

Line insulator development history

Porcelain Pin Insulators are used for insulating and suspending wires in high-voltage and ultra-high voltage AC and DC transmission lines. In the early years, glass insulators were mostly used for telegraph poles, and slowly developed a lot of disk-shaped insulators hung on one end of the high-voltage wire connection tower. It was to increase the creepage distance, usually made of glass or ceramic, called insulators.

The structure of line insulator products

The product is composed of iron caps, stain-resistant glass parts, and steel feet, which are glued together with cement glue. This product all adopts the internationally better cylindrical head structure, which is characterized by a small head size. Lightweight, high strength and large creepage distance. Can save metal materials and reduce line cost. In order to meet the needs of live working, the domestic traditional structural shape is adopted on the brim.

Line insulator operation

Zero value self-braking, easy to detect

The stain-resistant glass insulator has the characteristics of zero value self-breaking. As long as the observation is done on the ground or on a helicopter, there is no need to climb the pole to detect piece by piece, which reduces the labor intensity of workers.

The products introduced into the production line have an annual operating self-break rate of 0.02-0.04%, which can save line maintenance costs. Good arc resistance and vibration resistance.

In operation, the new surface of the stain-resistant glass insulator suffering from lightning burns is still a smooth glass body and has a toughened internal stress protection layer, so it still maintains sufficient insulation performance and mechanical strength.

In the 500kv line, there have been many disasters caused by the movement of the wire running on ice. The glass insulator after the wire movement has been tested, and the electromechanical performance has not been degraded.

Porcelain Pin Insulators

Porcelain Pin Insulators

Good self-cleaning performance and not easy to age

According to the general report of the electric power department, the glass insulators are not easy to accumulate dirt and are easy to clean. The glass insulators running on the southern line are washed clean after rain.

Regular samples of glass insulators on lines in typical areas are taken to determine the electromechanical performance after the operation. The accumulated data show that the electromechanical properties of glass insulators after 35 years of operation are basically the same as those at the factory without aging.

The main capacity is large, the voltage distribution in the string is uniform, and the dielectric constant of the glass is 7-8 so that the tempered glass insulator has a large main capacitance and the voltage distribution in the string is uniform, which is beneficial to reduce the load on the insulator near the wire side and the ground side Voltage, so as to achieve the purpose of reducing radio interference, reducing corona loss and extending the life of glass insulators, operation practice has proved this.

Some enhancers are located upstream of the promoter and some are located downstream, so the effect of the insulator does not depend on the relative position of the insulator and the promoter. Composite insulators, Therefore, the reason for the directionality of the insulator effect has not really been clarified. It has been found that two loci affect the function of insulators in a trans-activation manner.