Professional Insights on Composite Insulators, Surge Arresters ...

Insulators have an important role in power transmission and distribution in the field in which electricity is transmitted over long distances without danger to it or human life. Two commonly used insulators in modern power systems are composite insulators and polymer insulators. Although these terms are often used interchangeably there are some important differences between them.

Please visit our website for more information on this topic.

What are composite insulators?

The modern alternative to traditional ceramic and glass insulators is composite insulators. Usually, FRP (fiberglass reinforced polymer) composites are used to make the core of the composite insulator, as they give the mechanical stability necessary to endure the very high tensile stresses in transmission lines. Silicone rubber or similar polymer material surrounds the core to provide very good electrical insulation, as well as environmental hardness.

What are polymer insulators?

Polymer insulators are external insulators using polymer materials as insulators. In this case, the material being used to texturize the outer shell is known as a polymer (usually silicone rubber, EPDM rubber, or some similar compound). Internal structures of polymer insulators may differ but the common feature of all the polymer insulators is using polymer materials as external insulation.

Material Comparison

The main difference compared to polymer insulators is made up of the material composition. The composite insulators contain a fiberglass-reinforced polymer (FRP) core, covered with a polymer material, usually silicone rubber. The dual material design enables the composite insulators to have a very high level of mechanical strength and flexibility.

However other insulators, including polymer insulators, do not use fiberglass in their cores and instead depend on polymer materials to encompass their outer shell. This difference rests primarily in the material composition and the internal structure, but are both polymers key components of the design.

Performance in different environments

Pollution resistance

Composite insulators have a strong pollution resistance due to their pollution resistance, which is the outer hydrophobic silicone rubber shell of the composite insulators that prevent the accumulation of pollution (dust, dirt, and salt). In areas where saline environments surround the insulators and high pollution levels are present, this is an important point. Because silicone rubber is water-repellent, it denies the formation of conductive films, which reduces the risk of flashover. Good pollution resistance is also given by polymer insulators. However, the overall performance of these polymers in polluted environments will depend on the specific polymer they will be made from. Polymer insulators are the most widely used types, and silicone rubber is the best pollution-resistant polymer insulator.

Weathering and UV Resistance

Composite and polymer insulators are designed to resist degradation by the environment including UV radiation, extreme temperatures, and moisture. A silicone rubber shell of composite insulators has excellent long-term UV resistance and will not crack or deteriorate over time. Unlike silicone rubber, polymer insulators (based on the type of polymer) tend to have good weathering resistance — but some may deteriorate more quickly than silicone rubber in the case of intense solar radiation or severe weather conditions.

Mechanical Strength

Related links:
DC/AC Hipot, insulation test - Mike Holt's Forum

You will get efficient and thoughtful service from ZheXi.

Composite insulators with fiberglass cores provide excellent mechanical strength in tensile loads and are thus suitable for use in applications requiring high tensile loads. For example, for long spans between transmission towers or other sites likely to experience high winds and other mechanical stresses, composite insulators are the ideal choice. While polymer insulators are mechanically strong, they may not be sufficiently strong in tension, depending on how much reinforcement from glass fibers is present in the core, compared to composite insulators. But they are still rugged enough for use in medium and high-voltage applications.

Composite Insulators VS Polymer Insulators

Composite and polymer insulators have much in common (many of which the utility will appreciate), such as the use of polymers as insulators and lightweight, pollution-resistant design, but there are important differences between the two. Glass fiber reinforced polymer core makes composite insulators excellent mechanically and good mechanically, therefore composite insulators are highly suitable for high tension applications. Meanwhile, polymer insulators are a broader category of a wide variety of polymer-based designs that offer flexibility as to what materials can be used in the core and casing.

Silicon rubber insulators, commonly known as polymer insulators are available in the market in a wide range of capacity starting from 10kv to 500kv. These are Polymer Disc Insulators, which are lightweight, very handy, and easy to use.

Let us have a broader concept of these polymer insulators.

Range of composite polymer insulators

The typical polymer insulators or silicon rubber insulators include the following types:

• Polymer Lighting Arrester
• Polymer Disc Insulator
• Electrified Railway Polymer Insulators
• Cross Arm Silicon Rubber Insulators
• Station Post Polymer Insulators
• Pin Type Composite Insulators
• Suspension Long Rod Silicone Rubber Insulators

Advantages of using composite polymer insulators over the traditional porcelain insulators

Over the last decade, polymer insulators have successfully replaced the traditionally used porcelain insulators in almost all fields. The distinct advantages of the Composite Polymer Insulators over the porcelain ones are listed below:

• As compared to the porcelain insulators, the polymer ones are not brittle. This reduces your requirement of spare – parts of the insulators to a great extent, thus reducing running cost.
• The polymer insulators, as compared to the porcelain ones are easy to carry due to their much lower weight. The transportation cost and the risks of transit time damage are also minimized.
• With the silicon insulators, there is absolutely no necessity for zero – value checking.
• The maintenance cost of polymer insulators is a minimum, as you do not need to clean them very often. The hazards of maintenance being the minimum, you can easily consider using them in areas, which are extremely difficult to maintain.
• The polymer insulators have proved to be extremely anti-pollutant. They can be used very well in highly polluted locations.
• The polymer ones come with high mechanical strength, while the same cannot be guaranteed about the porcelain insulators, which are essentially breakable.

Why should you get the best composite polymer insulators in the market?

Whether you go for a ceramic insulator or a polymer one, the most important factor that will matter is the reliability of the insulator. This factor exclusively depends on the mechanical potency of the polymer line post insulators. However, with the latest technology of manufacturing the polymer insulators, like the fixture and mechanical moulding techniques, the insulators are quite reliable in their durability. However, what cannot be fully guaranteed is the electrical strength.

Therefore, it is best for you to concentrate on the other issues while making your comparative estimates of various types of polymer and ceramic insulators available in the market.

A composite insulator is one, which is mainly suitable for outdoor use. Its fibre rod structure remains coated with weather resistant fillers and rubbers. It is also fitted with fittings at the end. The outdoor insulators have to consider the most important issue of the edge between the surrounding air and the insulating body.

Problems are faced when the interface is affected by nitric acid in air, salt, dust, rain etc. these external factors deteriorate the performance of the insulator. A polymer composite insulator can prevent these in a much better way than the porcelain ones.