Lightning arrester

Lightning Arrester

A lightning arrester or surge arrester is a device used in electrical power systems and telecommunications systems to protect the insulation and conductors of the system from the damaging effects of lightning. The primary purpose of a lightning arrester is to divert the high voltage surges of a lightning strike to the ground, away from the equipment it is protecting.

Overview

Lightning arresters are an essential component in any electrical system that is exposed to lightning strikes. They are typically installed on transformers, transmission lines, and at substations, as well as on buildings and other structures prone to lightning strikes. The device functions by providing a low-resistance path to ground for the lightning surge, thus protecting the electrical equipment from the high voltage spike.

Types of Lightning Arresters

There are several types of lightning arresters, each designed for specific applications and voltage levels. The most common types include:

• Rod Gap Arrester: A simple form of arrester that consists of two rods with a gap in between. It is now largely obsolete due to its inability to quench the follow current.
• Valve Type Arrester: Uses a series of semiconductor elements to provide a high resistance to normal voltage and a low resistance to surge voltage.
• Metal Oxide Varistor (MOV) Arrester: The most widely used type today, MOV arresters offer superior protection and can handle multiple lightning strikes without degradation.
• Expulsion Type Arrester: Contains a gas-filled chamber that is ionized by the surge, creating a path to ground. It is mainly used in medium voltage systems.

Installation and Maintenance

Proper installation and maintenance of lightning arresters are crucial for their effective operation. They should be installed as close as possible to the equipment to be protected, with minimal lead lengths to ensure rapid response to surges. Regular inspection and testing are necessary to ensure that the arresters are functioning correctly and have not been damaged by previous surges.

Safety Considerations

While lightning arresters significantly reduce the risk of damage from lightning strikes, they cannot offer absolute protection. It is also essential to implement a comprehensive lightning protection system, including grounding and bonding, to provide the best possible defense against lightning damage.

Conclusion

Lightning arresters play a critical role in protecting electrical and telecommunications systems from the potentially devastating effects of lightning strikes. By diverting surge voltages safely to the ground, they prevent damage to equipment and ensure the reliability and safety of power and communication networks.

Lightning arrester Resources
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