WHAT IS INSULATOR?

An insulator is a device installed between conductors at different electrical potentials or between conductors and components at ground potential. It is capable of withstanding voltage and mechanical stress. The primary function of insulators is to provide electrical insulation and mechanical support, ensuring the safe operation of power transmission lines. Insulators prevent the passage of electric current while enduring mechanical forces.
Insulators play a crucial role in power transmission. In the past, insulators were commonly used on utility poles. With technological advancements, they gradually evolved to hanging arrangements on one end of high-voltage power transmission towers to increase the creepage distance. Insulators are made from various materials, including porcelain insulators, glass insulators, and composite insulators. Insulators are categorized based on different characteristics:

• By installation method: Suspension insulators (used in overhead power lines) and post insulators (used in power plants and substations).
• By Insulating material: Porcelain insulators, glass insulators, and composite insulators.
• By voltage level: Low-voltage insulators and high-voltage insulators.
• By environmental conditions: Derivatives such as pollution-resistant insulators.
• By breakdown potential: Divided into Type A insulators (non-breakdown type) and Type B insulators (breakdown type).

Different types of insulators possess their characteristics:

• Suspension insulators, including disc and rod types, are widely used in high-voltage overhead power lines.
• Post insulators are used in power plants and substations, and are also components of electrical equipment like isolation switches and circuit breakers.
• Porcelain insulators are commonly used and have good mechanical strength.
• Glass insulators possess the self-explosive feature, eliminating the need for zero-voltage testing during operation.
• Composite insulators are lightweight and offer excellent pollution resistance, although their aging capabilities are not as strong as porcelain and glass insulators.
• DC insulators are suitable for direct current transmission, offering longer creepage distances.
• Pollution-resistant insulators are designed to enhance electrical strength and pollution flashover performance by increasing umbrella skirts or modifying their structure.

The design and selection of insulators should be tailored to specific requirements and environmental conditions to ensure the stable and secure operation of power transmission lines.