How to choose a suitable Insulator？

An insulator is an electrical insulation component installed between conductors of different potentials or between conductors and ground potential components. Its main function is to support and fix the current-carrying conductor and maintain a good insulation state between the current-carrying conductor and the ground or between conductors of different potentials.

Insulators are indispensable electrical equipment in power systems and are widely used in transmission lines, substations, power plants and other places. The quality and performance of insulators are directly related to the safe and stable operation of power systems.

Different types of insulators have different performance and characteristics. They are suitable for different machines and environments, so choosing a suitable insulator is crucial because it is related to adaptation and safety issues.

Determine the rated voltage of the insulator according to the voltage level of the power system. The rated voltage of the insulator should be higher than or equal to the system operating voltage to ensure that electrical faults such as breakdown will not occur under normal working conditions. For example, for a 110kV transmission line, an insulator with a rated voltage of 110kV or above should be selected.

Consider the possible overvoltage conditions in the system, such as lightning overvoltage, operating overvoltage, etc. The insulator should be able to withstand these overvoltages without damage to ensure the safe and stable operation of the system.

Select insulators with high insulation resistance to reduce leakage current. High insulation resistance can reduce power loss and improve the efficiency and safety of the system. Generally speaking, the insulation resistance of the insulator should be above several hundred megohms.

Insulation resistance is affected by environmental factors such as humidity, temperature, and dirt. In a humid or dirty environment, the insulation resistance may decrease, so it is necessary to select insulators with good pollution resistance and moisture resistance.For example, glass insulators have high dielectric strength, resistivity and tensile strength, and can operate stably under different voltage levels and mechanical loads, ensuring the reliability of transmission lines.

If the insulator is installed in a severely polluted area, such as an industrial area, coastal area, etc., it is necessary to select an insulator with good pollution flash resistance performance. Pollution flash resistance insulators usually adopt special designs or materials, such as polymer insulators, whose surface is hydrophobic, which can reduce the accumulation of dirt and the adhesion of water, thereby reducing the risk of pollution flash.

The pollution flash resistance performance of the insulator can be evaluated by the creepage distance ratio of the insulator. The creepage distance ratio refers to the ratio of the creepage distance on the surface of the insulator to the maximum operating voltage of the system. The larger the creepage distance ratio, the better the pollution flash resistance performance.

Insulators need to withstand mechanical loads such as gravity, wind, and ice on the conductor, so they must have sufficient mechanical strength. Calculate the mechanical strength requirements of the required insulators based on factors such as the line span, conductor tension, and meteorological conditions.

Consider the impact and vibration that the insulators may be subjected to during installation and operation, and select insulators with certain impact and vibration resistance. For example, in mountainous areas or earthquake-prone areas, insulators with higher seismic resistance should be selected.

For suspension insulators, their tensile strength is particularly important. Tensile strength determines the reliability of the insulator when it withstands the tension of the conductor. According to the maximum tension and safety factor of the conductor, select a suspension insulator with sufficient tensile strength.

Check the quality of the insulator's connection hardware and accessories to ensure that they can work well with the insulator and bear the mechanical load together.

Consider the ambient temperature range of the insulator. In cold areas, the insulator should be able to withstand low temperatures without cracking; in hot areas, it should be able to maintain stable performance at high temperatures. Select insulator materials with suitable temperature characteristics, such as porcelain insulators can withstand temperatures up to 1000°C and can still maintain good insulation and mechanical properties in high temperature environments, making them suitable for various harsh climatic conditions.Temperature changes may cause changes in the size and mechanical properties of the insulator, so it is necessary to select insulators with good temperature compensation performance.

In a high humidity environment, a water film is easily formed on the surface of the insulator, reducing the insulation performance. Select insulators with good moisture resistance, such as insulators made of hydrophobic materials or moisture-proof treatment.

For insulators that are in a humid environment for a long time, their corrosion resistance also needs to be considered to prevent damage due to the combined action of moisture and corrosive media.

Insulators need to be exposed to the outdoor environment for a long time and withstand the influence of natural factors such as sun, rain, and wind. Select insulators with good weather resistance, and their materials should have properties such as UV resistance, oxidation resistance, and aging resistance.