Line Post Insulator

Porcelain Line Post Insulator are divided into eight grades of 95, 105, 125, 150, 170, 200, 250 and 325kV according to the rated lightning impulse withstand voltage value; according to the rated bending damage load value, they are divided into 3, 5, 8 and 12.5kN Four grades; according to the installation method, it is divided into two types: vertical installation and horizontal installation; There are two types: threaded connection and inseparable type.

Purpose and usage environment

Outdoor solid rod-shaped pillar insulators are used in outdoor power stations, substation power distribution devices and electrical equipment with power frequency AC voltage of 10-500KV as insulation and support for live parts.

The applicable environment of Juetaizi is -40-~+40, and some products can be used in areas with an altitude of 4000m. The products are divided into two categories: ordinary type and stain-resistant type. The stain-resistant type can be applied to medium, heavy and extra-heavy stained areas.

Structural and process characteristics

The modified series of gingival insulating porcelain parts have a solid structure, and the adhesive part adopts a cylinder sanded structure. The porcelain formula of our factory is advanced and has excellent performance. After actual operation, the reliability is very high. The sand used for sanding is special granulated sand that has undergone strict process control. It has excellent bonding properties with the porcelain body and a reasonable expansion coefficient, which can effectively improve the mechanical strength of the product. The flange structure of the product is reasonable, and the stress is evenly distributed when subjected to force. Its material is ductile iron with high mechanical strength and its surface is hot-dip galvanized. Has excellent rust resistance. The cement used for glue installation is high-grade cement, coupled with reasonable maintenance technology, the strength of the porcelain has been fully exerted. Products of any voltage level are single-column type, which has the advantages of simple structure, long operating life and low maintenance workload. In order to ensure the reliability of insulators, our factory conducts individual impact, ultrasonic flaw detection and four-way bending load test on the products.

In order to achieve the optimal selection of post insulators for different substation applications (e.g. AIS isolating switches), different technical parameters need to be considered. Specifically, important factors to consider when optimizing the size and dimensions of post-mounted insulators are mechanical, electrical, environmental, functional, and economical.

Depending on the application, many different types of post insulators are used in substations and substations, such as as busbar supports, smoothing reactor supports, switchgear, etc. For AIS isolating switches, the key requirements can be divided into three main categories:

Functional and electrical requirements

The main function of the isolating switch is to ensure safety: in the open state it must provide a visible and reliable disconnection gap, while in the closed state it must withstand the flow of normal and fault currents without interruption or abnormality unsafe conditions. In practice, the isolating switch must avoid discharges through open air gaps and to the ground.

Mechanical requirements

From a mechanical point of view, the isolating switch must withstand external loads in addition to its own operating load. For example, on UHV equipment, one of the most severe conditions is the seismic hazard, so a highly precise design is necessary if all seismic requirements are to be met. Other loads to consider are short circuits, high speed wind and terminal loads.

Environmental requirements

Isolating switches are fully exposed to the environment and must withstand environmental factors such as severe icing (a very important factor as it completely changes the performance of the insulator) or heavy rain, which increases the risk of discharge. On top of that, contamination is a major factor in determining size, as insulation failure can lead to discharges to ground.

All these requirements are closely related to the performance of the insulator, which makes the rear insulator one of the most important elements in disconnectors as well as many other substation applications. Considering the other requirements related to displacement under the load in use, isolating switches actually have another critical issue that other types of equipment do not face - namely, the movement of the mechanical parts required to open and close the equipment. Therefore, in order for such equipment to work properly, it must have a certain prescribed rigidity.

In addition to the above limitations, for most open-air substations today, it is necessary to provide a compact and cost-effective solution. The development of station column insulators can contribute significantly to achieving this goal by limiting the necessary arcing distances of busbars, isolating switches and other station equipment. This can be achieved by optimizing the post-insulator design, for example by selecting the most suitable materials, by increasing mechanical strength and stiffness, reducing the number of stacking/intermediate flanges and optimizing the shed profile and creepage coefficient.

For UHV, the main challenge with rear insulators is related to height, especially since contaminated environments often require extremely long creepage distances. The associated mechanical requirements from bending and torsional loads only complicate the challenge and significantly increase the difficulty of fabricating such units.

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