The Difference Between Polymer Insulators And Porcelain Insulators

Insulators are important items in power lines, they are widely used in all circuits and electrical or electronic systems to isolate the electricity between two conductive materials. We are talking today about polymer insulators and porcelain insulators used on high voltage overhead lines.

What is a polymer insulator?

Polymer insulators are a special type of insulation control element that plays an important role in overhead transmission lines. There are many types of polymer insulators. Polymer suspension insulators; polymer pin insulators; polymer station post insulators; polymer line post insulators etc.

110kV Polymer Suspension Insulators

What is a Porcelain Insulator?

Porcelain is made from a refined white clay called kaolin, which is fired at temperatures of up to 2,600 degrees Fahrenheit. It is sometimes referred to as "China" because the manufacturing process was developed in that country centuries ago.

Porcelain is also available in solid colours, usually white. Porcelain is denser and less absorbent than ceramic, so it can easily withstand humidity and harsher weather conditions. Porcelain is more expensive to produce due to the cost of materials and the intensive manufacturing process.

Thanks to their durability, porcelain insulators come with a lifetime warranty against typical wear and tear. Porcelain insulators are ideally suited for fences that are subjected to a great deal of stress and strain, such as those exposed to extremely cold temperatures or aggressive animal pressure.

Porcelain Post Insulator

What’s the difference between polymer insulators and porcelain insulators?

First of all, we can easily tell an obvious difference from their names: the materials.

Polymer insulators consist of several parts: tthe core inside, which cannot be seen from appearance, is made of fiberglass. Sometimes we can see the red or grey exterior, which is made of silicone rubber, which is why it is called "polymer". At the top and bottom, the polymer insulator usually has two metal ends, which are called "fittings". The fittings are made in a shape with standard connections and these allow the insulator to be connected to other insulators or accessories in the overhead line.

Let’s see the composition of porcelain insulators. The major part is made of porcelain. Here the major part means the insulating part, where we see many sheds and grooves. These insulator sheds are manufactured into such shapes to increase the insulating surface, which we call “creepage distance”. On the top and bottom ends, porcelain insulators also have 2 metal fittings, serving for the same purpose as mentioned above.

33kV Polymer Pin Insulator

Apart from the difference in material, here is something more important: the properties and performance.

Porcelain is an excellent insulating material and people discovered this property a long time ago, which is why it was first used for high voltage insulators. With the development of technology, silicone rubber came into the picture, which offers even better insulating properties. In addition, silicone rubber has excellent hydrophobic and hydrophobic mobility. This means that when dirt and dust accumulate on the insulator's surface, especially in outdoor environments, the loss of insulation properties becomes more pronounced. The hydrophobicity and hydrophobic fluidity of silicone rubber insulators are dominant.

138kV Polymer Station Post Insulator

Polymer insulators and porcelain insulators also differ in their mechanical properties.

Porcelain insulators, especially post type porcelain insulators, have better performance on cantilever loads. This comes from the physical composition of the rigid porcelain material. In contrast to the porcelain core of porcelain insulators, the core of column polymer insulators is FRP, made of tens of thousands of glass fibre filaments and bonded with epoxy resin. This may achieve the same specified mechanical cantilever load, but due to its properties it has better deformation and displacement. This is not preferred in high voltage power substations.

For suspension and tension type insulators, the FRP core shows its advantage in tensile performance. The filament provides an excellent property in bearing tensile strength in the radial direction.

As a professional insulator supplier, SAA GRID offers polymer insulators and porcelain insulators, etc. They are manufactured in various sizes and also as per customers' requirements. For more information and consultation, contact us here!