What is a Lightning Arrester

Summary

This video explains the role of lightning arresters in protecting power systems from lightning surges and switching surges. While lightning rods protect structures, lightning arresters are used in power systems to safeguard equipment and insulation from high-voltage damage. The video highlights how arresters, often containing Metal Oxide Varistors (MOV), divert dangerous surges to the ground without absorbing or stopping lightning. The MOV component acts as a fast-acting switch, preventing overvoltage from reaching sensitive equipment. This concise explanation helps viewers understand the importance of lightning arresters in maintaining power system reliability and equipment safety.

Takeaways

• 😀 A lightning arrester protects power systems from lightning and switching surges, typically in systems above 1,000 volts.
• ⚡ A lightning rod diverts lightning to the ground but does not function as an arrester. Lightning rods are conductive terminals always at ground potential.
• 🔌 Lightning arresters protect equipment insulation from damage by limiting the voltage produced by lightning, rather than absorbing or stopping the lightning itself.
• 💡 Surge protection devices (SPDs) and TVSS are similar to lightning arresters but are used in systems with voltages below 1,000 volts.
• 🌩️ Lightning arresters work by diverting the lightning current to the ground, preventing damage to equipment connected to the system.
• 🔧 The MOV (Metal Oxide Varistor) disk is the core component of a lightning arrester, acting as a fast-acting electronic switch that limits voltage during a lightning surge.
• 🔬 Under normal voltages, the MOV disk is an insulator, but during high voltage from a lightning strike, it becomes a conductor and diverts the surge.
• 🧑‍🔬 The MOV disk consists of billions of microscopic junctions of metal oxide grains, which act as electronic switches to form a current path during a lightning surge.
• ⚙️ The MOV disk's action is rapid—switching on and off in microseconds to prevent voltage from damaging sensitive equipment.
• 🌍 A lightning arrester protects equipment that is electrically in parallel with it, ensuring that only the targeted components are safeguarded from lightning damage.
• 📚 The video concludes by emphasizing that Arrestor Works provides valuable surge protection resources and encourages feedback from viewers.

Q & A

What is the primary difference between a lightning rod and a lightning arrester?

A lightning rod protects structures from lightning by diverting lightning surges to the ground. However, it is not an arrester. A lightning arrester, on the other hand, is specifically designed to protect electrical systems, such as transformers, from damage caused by lightning and switching surges in power systems above 1,000 volts.

What role does a lightning arrester play in power systems?

A lightning arrester protects power system equipment by diverting lightning surges to the ground, preventing damage to sensitive equipment insulation and ensuring the continued operation of the system.

How does a lightning arrester work to protect a transformer during a lightning strike?

When lightning strikes a power line, the arrester activates and diverts the surge to the ground, thereby protecting the transformer from damage. This prevents a power outage, keeping the lights on.

Does a lightning arrester absorb lightning?

No, a lightning arrester does not absorb lightning. It does not stop lightning but rather limits the voltage caused by the lightning surge and diverts the current safely to the ground.

What type of equipment does a lightning arrester protect?

A lightning arrester protects equipment that is electrically in parallel with it, such as transformers and other sensitive components in power systems.

What is a Metal Oxide Varistor (MOV) and how does it relate to a lightning arrester?

A Metal Oxide Varistor (MOV) is a semiconductor component used in lightning arresters. It is normally an insulator at standard voltages but becomes a conductor when exposed to high voltages, such as those from a lightning strike. This action helps the arrester divert the surge to the ground.

How does the MOV material in a lightning arrester work during a lightning surge?

During a lightning surge, the MOV material acts as a fast-acting electronic switch, turning from an open switch under normal conditions to a closed switch when the surge occurs. This creates a current path from the top terminal of the arrester to the ground terminal, diverting the surge away from the equipment.

What is the significance of the billions of microscopic junctions in a lightning arrester?

The billions of microscopic junctions of metal oxide grains within the arrester allow it to rapidly switch on and off in microseconds. This creates an effective current path during a lightning surge, protecting the equipment by preventing overvoltage conditions.

How fast does the MOV disc in a lightning arrester react to a lightning strike?

The MOV disc in a lightning arrester reacts in microseconds, which is fast enough to divert the surge and protect the equipment before damage can occur.

Can lightning arresters protect systems with voltages below 1,000 volts?

No, lightning arresters are typically designed for power systems above 1,000 volts. For systems with voltages below 1,000 volts, surge protection devices (SPDs) or transient voltage surge suppressors (TVSS) are used instead.