How to Choose Aerodynamic Glass Insulator?

A high voltage glass insulator is an element designed to support and insulate high voltage electrical conductors in electrical energy distribution and transportation systems. It is composed of a tempered glass disc that can have different shapes depending on its function and specific application, to which a metal cap and pin are attached that allow the insulators to be joined forming insulator strings. These insulators are essential to maintain the integrity of the electrical system and prevent short circuits or electrical shocks.

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• It is designed to withstand high voltages.
• It can have different shapes depending on its function.
• It is essential for the integrity of the electrical system.

Each insulator model is defined by a series of parameters defined by the manufacturer and can be seen in the catalogue or on the drawings of each insulator, and which must comply at least with the minimum or maximum values ​​required by the different applicable standards The main parameters include the mechanical (mechanical breaking load), the dimensional (coupling standard, diameter, creepage distance and pitch), the geometric (shape of the insulator profile) and the electrical ones (electric withstand voltages for puncture, dry and wet power frequency, and lightning impulse withstand voltages). For each power line project, the required chain parameters must be properly calculated, and the most appropriate insulators must be chosen for each case.

• Mechanical parameters
• Electrical parameters
• Dimensional and geometric parameters

Proper installation and maintenance of high-voltage glass insulators are essential to ensure their optimal operation and prolong their lifespan. The installation process typically involves securely fastening the insulators to support structures using appropriate hardware and tools for the specific environment. Additionally, in highly polluted environments, regular inspection procedures should be followed to detect excessive contamination, and corrective measures should be taken as necessary to prevent premature failures.

• Secure fastening to support structures.
• Regular inspection to detect excessive contamination.
• Proper maintenance to prolong lifespan.

High-voltage glass insulators are primarily made of high-quality tempered glass, which is capable of withstanding significant mechanical and thermal stresses, while also enduring high levels of electrical tension without damage.

In addition to glass, complementary materials such as cast iron, forged steel, cement, and stainless steel are used for the fastening fittings. These materials are designed to withstand adverse environmental conditions and ensure the stability and durability of the insulator throughout its lifespan.

For very high contamination environments, the SILGLASS® solution adds a thin layer of room temperature vulcanizing (RTV) silicone to the glass surface of the insulator, which imparts hydrophobic properties, adding performance benefits against contamination.

• High-quality tempered glass.
• Metallic materials for the fittings.
• Cement as a fastening element for the components.
• RTV silicone coating for SILGLASS® insulators.

Contamination, such as the accumulation of salts, dust, or other natural or artificial elements, combined with moisture on the surface of glass insulators, can significantly affect their performance and effectiveness. This contamination can lead to a decrease in the dielectric strength of the insulator chain, increasing the risk of electrical arcs and shocks. On the other hand, excessive contamination without taking mitigation measures can potentially accelerate the aging of insulators due to corrosion.

• Decrease in the insulation capacity of the chains.
• Increased risk of electric arcs.
• Potential accelerated aging of insulators.

To mitigate the effects of pollution, several measures can be taken. First of all, the type of contamination that affects the line must be studied (sources, characteristics of the contaminant, etc.) and the severity of the pollution at the location must be determined. You must choose the appropriate insulator profile for each environment (standard, anti-pollution, aerodynamic…), design the chains with sufficient specific creepage distance. Also install adequate protection against corrosion (sacrificial zinc ring, standard or reinforced galvanization). And in extreme cases, minimize leakage current by applying RTV silicone creating a hydrophobic layer to the insulators.

• Analysis and study of contamination
• Proper selection of the profile of the insulators and the creepage line of the chains
• Protection against corrosion
• RTV silicone application

High voltage glass insulators are subject to specific standards or technical specifications that regulate their design, manufacturing and testing. These regulations may vary by country but are usually guided by the standards established by the International Electrotechnical Commission (IEC) or the American National Standards Institute (ANSI). These standards provide detailed guidelines on the quality requirements that insulators must meet to ensure their suitability and reliability in high voltage applications.

• Standards for design, manufacturing, and testing.
• International standards such as IEC and ANSI.
• Quality requirements.

In addition to glass insulators, there are porcelain insulators and polymer insulators.

Glass insulators, like porcelain ones, are cap and pin insulators or chain insulators that are coupled together to form insulator strings, whereas polymer insulators are single-piece elements.

The most important advantages of glass insulators over porcelain and composite or polymeric insulators are the following:

• Ease of visual inspection: A glass insulator, when it has a defect or is perforated, shatters completely, making it easily detectable with the naked eye from the ground without the need for expensive inspection systems. Even if an insulator shatters, both the mechanical and electrical properties of the insulator string remain almost intact (LGI guarantees a residual strength of the “insulator whose insulating part has shattered” of at least 80%, and the loss of leakage distance in the entire string is relatively small), so urgent action is usually not necessary. The insulator can be replaced later during the next scheduled maintenance operation. In any case, the annual rate of spontaneously shattered insulators is statistically very low with experienced and high-quality glass manufacturers, with less than 1 insulator shattered per 10,000 insulators in service.
• Greater durability: Glass insulators do not degrade and have a longer lifespan compared to others, especially polymer insulators. The lifespan of a glass insulator exceeds 50 years, often exceeding the expected lifespan of the electrical transmission line.
• High mechanical and electrical strength: Glass insulators are known for their higher mechanical and dielectric strength.
• Environmental advantages: Its longer lifespan, the fact that glass is a 100% recyclable material, and its manufacturing process having a lower environmental impact make glass insulators more sustainable than others.
  • Greater ease of inspection
  • Greater durability
  • High mechanical and electrical strength
  • Environmental advantages

The use of high voltage glass insulators can provide several environmental benefits compared to other types of insulators. For example, and unlike polymeric insulators, the expected useful life of a glass insulator is greater than 50 years, which usually exceeds the useful life of the line itself; This means that throughout the life of the line it is not necessary to renew the insulation, reducing the number of insulators that need to be manufactured and saving those associated resources.

On the other hand, glass is a recyclable material, which means that glass insulators at the end of their useful life can be recycled and reused instead of being disposed of in landfills. Additionally, glass insulators require fewer natural resources to manufacture compared to other materials such as porcelain, contributing to the conservation of natural resources and reducing the environmental impact associated with the production of electrical insulators.

• Longer lifespan than that of the line.
• Recyclable material.
• Lower consumption of natural resources.
• Reduction of environmental impact

A high voltage glass insulator, also known as a toughened glass insulator, is an electrical insulation component used in high-voltage transmission and distribution lines. It is typically assembled into insulator strings to support conductors and prevent current leakage. First manufactured around the s, the high voltage glass insulator has been widely used ever since due to its excellent mechanical strength and electrical performance.

If you want to learn more, please visit our website Composite Insulator.

How are High Voltage Glass Insulators Made?

The high-voltage glass insulator comprises a toughened glass disc, a hot-dip galvanized cap and pin, and a stainless steel security clip, all bonded with high-strength cement adhesive.

High Voltage Glass Insulator Manufacturing Process (How the Toughened Glass Disc Is Made)

1. Raw Material Preparation – 2. Melting – 3. Molding – 4. Annealing – 5. Toughening (Tempering) – 6. Quality Inspection – 7. Storage and Transportation

Production Line Diagram for High Voltage Glass Insulators

How do High Voltage Glass Insulators Work?

Mechanical Support
High voltage glass insulators withstand mechanical stresses such as tension, wind, and ice loads through:

• Tempered glass strength – Enhances durability and ensures line stability.
• Series configuration – Multiple insulators in a string adapt to different voltage and load requirements.
• Self-destruction feature – If broken, the glass shatters safely while metal fittings remain connected, preventing system failure.

Electrical Insulation
High voltage glass insulators prevent high-voltage conductors from leaking current to grounded towers or poles through:

• High resistance material – Glass is a poor conductor, effectively blocking current flow.
• Extended creepage distance – Disc or open-type designs increase the surface path to reduce flashover caused by pollution.
• Anti-pollution properties – The smooth glass surface resists dust accumulation, minimizing electrical breakdown risks.

How to Choose the Right High Voltage Glass Insulators: 3 Key Considerations

1. Drawings and Technical Parameters of High Voltage Glass Insulators

When selecting glass insulators, the following key technical parameters should be considered:

• Nominal Creepage Distance: A longer creepage distance helps prevent leakage or breakdown caused by surface polarization of the insulating material, ensuring the safe operation of electrical equipment.
• Minimum Mechanical Damage Load: For example, 120 kN (as shown in the drawing).
• Suitable Coupling Size: A standardized size facilitates the assembly of a stable insulator string.
• Hot-Dip Galvanized Accessories: Corrosion-resistant for long-term durability.

You can choose between IEC or ANSI international standards based on the requirements of your power transmission and distribution project. To purchase glass insulators, simply provide your drawings and technical specifications to the manufacturer for verification. They will then produce and quote based on your requirements.

2. Line Voltage Selection

The appropriate high-voltage glass insulator should be selected based on the line voltage. You can refer to the table below for guidance.

Based on Gaoya Power‘s 20 years of experience in supplying glass insulators:

• For 220 kV transmission lines, glass insulators with a mechanical strength of 160 kN or higher are recommended.
• For 500 kV and above ultra-high voltage (UHV) lines, glass insulators with a mechanical strength of 300 kN or more are typically used.

3. Environmental Considerations

Different environmental conditions require different types of high voltage glass insulators for optimal performance:

• Standard Glass Insulators: Suitable for low-pollution areas with conventional environmental conditions.
• Anti-Pollution Glass Insulators: Recommended for high salt fog, high humidity, and highly polluted areas, as they feature a longer creepage distance to prevent contamination-related failures.
• Aerodynamic Glass Insulators: Best suited for arid and sandy environments, where their streamlined design helps reduce dust and rain adhesion. These insulators are also ideal for use in deserts and industrial pollution zones.
• Standard Insulators in Cold Climates: In extremely cold environments without nearby pollution sources, standard glass insulators are an appropriate choice.

How do Pollutants Affect High-Voltage Glass Insulators?

Pollutants like dust, industrial emissions, salt spray, and bird droppings can weaken the performance of glass insulators in several ways:

• Reduced Insulation & Conductive Layer Formation
  Moisture turns surface contaminants into a conductive layer, increasing leakage current and possibly leading to arc discharge or flashover.
• Pollution Flashover Risk
  In humid or foggy conditions, pollutants lower surface resistance, making it easier for high voltage to break down the air, causing sudden short-circuit discharge.
• Increased Leakage Current & Energy Loss
  A continuous conductive path from wet pollutants raises leakage current, causing power loss, overheating, and faster aging of the insulator.

Four Solutions to Reduce the Effects of Pollution on High-Voltage Glass Insulators

• Use Anti-Pollution Insulators
  Designed with long creepage distances, these insulators extend the surface path for leakage current, reducing the risk of flashover.
• Perform Regular Cleaning
  High-pressure water washing or manual cleaning helps remove accumulated contaminants and maintain insulation performance.
• Apply Anti-Fouling Coatings
  Coatings like silicone rubber enhance water repellency, preventing moisture absorption and reducing flashover risk.
• Optimize Insulator Configuration
  Increasing the number of insulators improves the overall insulation level, reducing the impact of environmental pollution.

Why Choose High-Voltage Glass Insulators?