Lightning arrester and its types

What is Lightning Arrester?

A lightning arrester, also known as a Lightning diverter or Surge arrester, is a device designed to protect electrical and electronic equipment from damage caused by lightning strikes and power surges. Lightning arrester devices are commonly used in electrical power systems, telecommunication networks, and various other applications where sensitive equipment needs protection. The primary purpose of a lightning arrester is to divert excessive currents, such as those induced by lightning strikes or power surges, away from the equipment and into the ground, thereby preventing damage to the equipment. These devices are typically installed at points where power or communication lines enter a building or sensitive equipment is connected to the electrical network. The basic principle of a lightning arrester involves the use of a highly conductive material, such as a metal oxide varistor (MOV) or a gas discharge tube (GDT), which offers a low-resistance path for the surge current. When a high voltage surge occurs, the arrester quickly conducts the excess current to the ground, limiting the voltage that reaches the protected equipment.

Lightning arresters are available in different types and designs Such as:

1. Distribution Class Arrester: 

These are typically used in low-voltage distribution networks to protect residential, commercial, and industrial buildings from lightning-induced surges. The distribution class arrester rating is 1kV up to 36kV.

2. Intermediate Class Arrester: 

This type of Lightning Arrester is used in medium-voltage applications, such as electrical substations and industrial installations, to protect transformers, switchgear, and other equipment. The intermediate class arrester voltage rating is 3kV up to 120kV.

3. Station Class Arrester: 

These arrester types are used in high-voltage substations and power plants to safeguard large transformers, generators, and transmission lines from lightning strikes. Station class arrester available in rating 3kV to 684kV.

Lightning arresters should be regularly inspected and maintained to ensure their proper functioning. Over time, lightning arresters can degrade due to environmental factors and repeated exposure to surge events. If an arrester is damaged or worn out, it may not provide adequate protection and should be replaced.

Note: While lightning arresters can significantly reduce the risk of equipment damage, they do not guarantee absolute protection against lightning strikes. In extremely severe cases, direct lightning strikes or very close proximity strikes can still cause damage despite the presence of lightning arresters.

FAQs

What is the function of the lightning arrester?

The primary function of a lightning arrester is to provide a safeguard against lightning strikes by redirecting high voltage surges away from structures and sensitive electrical equipment. Lightning, with its immense energy, can cause irreparable damage to equipment and even lead to fire hazards. A lightning arrester functions to prevent such as:

1. Surge Diversion: The lightning arrester quickly detects this surge and provides a low-resistance pathway, creating a diversion route away from the components.

2. Voltage Regulation: A lightning arrester monitors and regulates the voltage within an electrical system. When the voltage exceeds a safe threshold, the arrester activates and establishes a conductive path to the ground, allowing the excess energy to be safely dissipated.

3. Equipment Protection: By redirecting high voltage surges, lightning arresters shield electrical equipment from the harmful effects of power spikes. These surges can damage sensitive electronics, such as computers, appliances, and industrial machinery. The lightning arrester acts as a barrier, absorbing and diverting the surge energy away from the equipment, thus safeguarding them from potential damage.

4. Safety Assurance: Lightning arresters contribute significantly to the safety of structures and individuals. By preventing high voltage surges from entering a building, they reduce the risk of electrical fires, explosions, and electrocution. 

What is the working principle of a surge arrester?

A surge arrester works by diverting excessive voltage surges or transient over voltages to the ground, thereby protecting electrical equipment from damage. It does so by utilizing a combination of a non-linear resistance element and a ground connection to safely dissipate the excess electrical energy.

Where is the lightning arrester placed?

Lightning arresters are typically installed at points where power lines or electrical equipment are susceptible to lightning strikes. They are commonly placed at the entrance of buildings, on utility poles, or near electrical transformers to divert lightning surges and protect the connected equipment from damage.

Which lightning arrester is mostly used?

The most widely used type of lightning arrester is the metal oxide varistor (MOV) arrester.

MOV arresters are generally the most commonly employed type due to their superior performance and cost-effectiveness.

Metal oxide varistor (MOV) arresters consist of a ceramic body made of metal oxide materials such as zinc oxide. MOV arresters are designed to protect electrical systems from voltage surges caused by lightning strikes and other power disturbances. They have a high resistance at normal operating voltage but rapidly decrease their resistance when the voltage exceeds a certain threshold.

What is required for a lightning arrester?

A lightning arrester requires a metal oxide varistor (MOV) or gas discharge tube (GDT) to provide a low-impedance path for lightning current. A proper grounding system is necessary for effective operation, allowing the current to safely dissipate into the ground. Some lightning arresters may include surge protective devices (SPDs) for additional protection. They should be mounted in a suitable location and housed in an enclosure for physical protection.

How much area does a lightning arrester cover?

The area covered by a lightning arrester depends on factors such as its design, installation location, and the specific equipment it is intended to protect. Generally, a lightning arrester can cover a localized area, such as a building or a specific electrical system, providing protection against lightning strikes and voltage surges within that area.

What is the difference between a lightning arrester and a surge arrester?

A lightning arrester primarily protects against high-energy lightning strikes, diverting the lightning current to the ground. A surge arrester, on the other hand, safeguards against voltage surges originating from various sources, including lightning, and is designed to clamp or divert excessive voltage to protect connected equipment.

How safe is a lightning arrester?

Lightning arresters are designed to enhance safety by providing protection against the damaging effects of lightning strikes. When properly installed and maintained, lightning arresters can significantly reduce the risk of equipment damage, electrical fires, and electrical hazards caused by lightning-induced surges.

What is the advantage of a surge arrester?

Surge arresters are also known as transient voltage surge suppressors. Its several advantages in protecting electrical systems and equipment from voltage surges:

• Equipment Protection.
• Enhanced Safety
• Extended Equipment Lifespan
• Improved System Reliability
• Versatile Protection
• Fast Response Time
• Cost-Effective Solution

What is the minimum size of wire for a lightning arrester?

The minimum size of wire for a lightning arrester depends on several factors, including the expected lightning current, the specific application, and the electrical codes or standards followed in your region. Generally, the wire size for a lightning arrester should be capable of handling the maximum anticipated current without significant resistance or voltage drop. There are two standard wire sizes for lightning arresters such as:

Class I – Copper: Minimum Gauge is 2 AWG, with a minimum individual strand size of 17 AWG.

Class II – Copper: Minimum Gauge is 00 AWG, with a minimum individual strand size of 17 AWG.

Conclusion

Lightning arresters provide essential protection against lightning-induced surges, safeguarding your electrical equipment from damage and maintaining system reliability. By investing in lightning arresters, you not only protect your valuable assets but also ensure the safety of individuals and minimize the risks associated with electrical disturbances.