What is Lightning Arrester - Complete Guide

What is Lightning Arrester? Complete Guide

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Lightning Arrester Installation and Lightning Protection System

What is Lightning Arrester?

A lightning arrester, also commonly called a surge arrester, is a protective electrical device used to limit transient overvoltage and divert surge current away from electrical equipment.

Lightning and switching events can produce high-voltage transients that may damage electrical equipment, insulation, transformers, control panels and other connected systems. A properly selected and installed surge protection device provides a controlled discharge path for these transient currents.

Lightning protection arrangements are commonly used in residential buildings, commercial buildings, factories, electrical substations, transformers, telecommunication installations, solar power systems and industrial facilities.

What is a Lightning Arrester?

A lightning arrester is a device designed to limit transient overvoltage and divert surge current away from protected electrical equipment.

Under normal operating conditions, the arrester normally presents high resistance and conducts only a small leakage current. When a transient voltage reaches the device's operating region, it becomes highly conductive and provides a path for the surge current.

Important: A lightning arrester is one part of a complete lightning and surge protection arrangement. Proper earthing, bonding, conductor routing and coordination of protective devices are also important.

How Does a Lightning Arrester Work?

The basic purpose of a lightning arrester is to limit excessive transient voltage and help prevent damaging surge energy from reaching protected electrical equipment.

During normal voltage conditions, the arrester remains in a high-resistance state. When lightning or switching activity produces a sufficiently high transient voltage, the device becomes conductive and diverts surge current through the protective discharge path.

After the transient event has passed, the arrester returns to its normal operating condition.

Basic Working Sequence

  1. Normal operation: The arrester remains in its normal high-resistance condition.
  2. Surge occurs: Lightning or switching activity produces transient overvoltage.
  3. Conduction: The arrester becomes conductive when the transient reaches its operating range.
  4. Surge diversion: Surge current is directed through the protective discharge path.
  5. Return to normal: After the transient passes, the arrester returns to its normal state.

Types of Lightning Arresters

Different surge arresters are used according to system voltage, electrical configuration, installation environment and protection requirements.

1. Metal Oxide Surge Arrester

Metal oxide surge arresters, particularly zinc-oxide-based devices, are widely used in modern electrical protection systems. Their nonlinear voltage-current characteristics allow them to conduct surge current during transient conditions while maintaining relatively high resistance during normal operation.

2. Distribution-Class Surge Arrester

Distribution-class arresters are used in electrical distribution systems to help protect equipment and networks from transient overvoltages.

3. Station-Class Surge Arrester

Station-class arresters are used for higher-level electrical installations such as substations and other high-voltage applications.

4. Low-Voltage Surge Protection Device

Low-voltage surge protective devices are commonly installed in electrical panels and distribution systems to reduce transient overvoltage reaching connected equipment.

Main Components of a Lightning Protection System

A complete lightning protection arrangement may include several interconnected components. The exact design depends on the building, electrical installation, risk assessment and applicable requirements.

Lightning Arrester Installation

Correct installation is important for effective surge protection. The device should be installed according to the manufacturer's instructions, electrical system characteristics and applicable technical requirements.

Important Installation Considerations

  1. Correct location: Install the arrester at an appropriate point in the electrical system where surge protection is required.
  2. Short connection path: Keep connecting conductors as short and direct as practical to reduce additional voltage during a surge.
  3. Proper earthing: Connect the protective device to an appropriate earthing and bonding arrangement.
  4. Suitable conductors: Select conductors according to the electrical design and applicable requirements.
  5. Protection coordination: Where multiple protective devices are installed, their characteristics should be coordinated appropriately.
  6. Inspection access: Provide suitable access for inspection and maintenance.

Applications of Lightning Arresters

Lightning arresters and surge protection devices may be used in many electrical and industrial applications, including:

Advantages of Lightning Arresters

How to Select a Lightning Arrester

Selection should be based on the electrical system characteristics, equipment requirements, expected surge conditions, manufacturer specifications and applicable technical requirements.

  1. System voltage: Select a device suitable for the nominal and maximum operating voltage.
  2. System configuration: Consider the electrical configuration, such as single-phase or three-phase systems.
  3. Equipment being protected: Identify transformers, panels, machinery, electronics or other equipment requiring protection.
  4. Surge exposure: Consider the lightning and switching transient exposure of the installation.
  5. Discharge characteristics: Select an arrester with suitable surge-current and energy-handling characteristics.
  6. Manufacturer specifications: Follow the manufacturer's technical documentation for selection and installation.

Lightning Arrester Testing and Maintenance

Periodic inspection and testing can help identify damaged components, deteriorated connections and other issues within a lightning and surge protection installation.

Inspection May Include

Testing procedures should be selected according to the arrester type, manufacturer's instructions, system voltage and applicable technical requirements.

Lightning Arrester vs Lightning Conductor

A lightning arrester and a lightning conductor have different functions within a lightning protection arrangement.

Lightning Arrester Lightning Conductor
Helps protect electrical equipment from transient overvoltage. Provides a conductive path for lightning current as part of an external lightning protection system.
Used primarily for electrical system and equipment protection. Used as part of the building's external lightning protection arrangement.
Diverts surge current through a protective discharge path. Conducts lightning current through the down-conductor system.
Commonly installed near electrical equipment or distribution points. Installed as part of the external lightning protection system.

Frequently Asked Questions About Lightning Arresters

What is a lightning arrester?

A lightning arrester is a protective electrical device designed to limit transient overvoltage and divert surge current away from protected electrical equipment.

What is the main purpose of a lightning arrester?

Its main purpose is to help protect electrical equipment and insulation from damaging transient voltage caused by lightning and other switching events.

How does a lightning arrester work?

During normal operation, the arrester presents high resistance. During a sufficiently high transient voltage, it becomes conductive and provides a path for surge current through the protective discharge system.

Where is a lightning arrester installed?

Lightning arresters may be installed at suitable points in electrical distribution systems, substations, transformers, panels and other installations requiring surge protection.

What are the different types of lightning arresters?

Common categories include metal oxide surge arresters, distribution-class arresters, station-class arresters and low-voltage surge protection devices. The appropriate device depends on the electrical system and protection requirements.

Is a lightning arrester the same as a lightning conductor?

No. A lightning arrester primarily provides protection against transient overvoltage in an electrical system, while a lightning conductor forms part of an external lightning protection system.

Why is earthing important for a lightning arrester?

The protective discharge path requires an appropriate earthing and bonding arrangement so that surge current can be diverted safely. The earthing system should be designed and installed according to the requirements of the electrical installation.

Does a lightning arrester protect against a direct lightning strike?

A lightning arrester is primarily intended to limit electrical-system overvoltage and divert surge currents. Protection against direct lightning strikes to a building requires an appropriately designed external lightning protection system.

Where are lightning arresters commonly used?

Lightning arresters are commonly used in residential and commercial buildings, factories, substations, transformers, solar installations, telecommunication systems, generators and industrial electrical installations.

Does a lightning arrester require maintenance?

Periodic inspection and testing can help identify physical damage, deteriorated connections and other problems. Maintenance should follow the manufacturer's recommendations and applicable installation requirements.

How do I select the correct lightning arrester?

Selection depends on factors such as system voltage, electrical configuration, expected surge conditions, equipment requirements, discharge characteristics and manufacturer specifications.

Can a lightning arrester be used for a transformer?

Suitable surge arresters are commonly used to provide overvoltage protection for transformers. The arrester rating and installation arrangement should be selected according to the transformer and electrical system characteristics.

Conclusion

A lightning arrester is an important protective device used to limit transient overvoltage and divert surge current away from electrical equipment.

Effective protection depends on appropriate device selection, installation, earthing, bonding, conductor routing and maintenance.

A complete lightning protection arrangement may also include air terminals, down conductors, earthing electrodes, bonding and surge protection devices. The equipment should be selected and installed according to the electrical system characteristics, manufacturer specifications and applicable technical requirements.

Lightning Protection & Earthing Services

Safeone Earthing provides lightning arrester supply and installation, lightning protection solutions, earthing system installation, earthing system design, earth pit testing and related electrical services for residential, commercial and industrial applications.