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Types of Lightning Arrester and Their Uses
What is Lightning Arrester?
A Lightning Arrester is a tool that shields various electrical devices and systems from the harm caused by lightning. It works using a technology called Corona Discharge.
Corona Discharge Technology operates by quickly releasing high voltage through the ionization of nearby air ions. The arrester typically has a high-voltage part at the top and a low-voltage part connected to the ground.
At Renown Power, we make a Home Lightning Protection System. In simple terms, this system for protecting homes from lightning uses a mix of highly conductive copper and aluminum alloys. This creates a path with low resistance to the ground, safeguarding the electrical system from damage caused by faulty currents.
Lightning Arrester Uses
Lightning arresters, also known as surge arresters, are like tiny electrical heroes, safeguarding crucial systems from the wrath of lightning strikes. Their primary use is to shield electrical power lines and telecommunication systems from the damaging effects of these high-voltage surges. But that’s not all! Let’s explore the full range of their protective powers:
Deflecting Lightning’s Fury:
- Imagine a lightning bolt zipping towards a power line. Instead of letting it wreak havoc, the arrester acts as a controlled path to the ground, diverting the immense current safely away from sensitive equipment. This prevents voltage spikes that could fry circuits and trigger fires.
Guarding the Grid:
- Power grids are the backbone of our modern world, and lightning arresters play a vital role in keeping them stable. By protecting them from lightning-induced disruptions, they ensure reliable electricity flow for homes, businesses, and vital infrastructure.
Safeguarding Communications:
- Lightning doesn’t just threaten power lines; it can also disrupt telecommunication networks. Telephone lines and internet cables are vulnerable to voltage spikes, but lightning arresters step in to shield these vital communication channels, ensuring smooth data flow and uninterrupted phone calls.
Beyond Lightning:
- While lightning is their main nemesis, arresters can also protect against other transient voltage spikes. These can occur due to switching operations within the power grid or even faulty machinery. By providing an alternative path for these surges, they shield electronics from unexpected jolts.
Applications Galore:
- From tall buildings and wind turbines to aircraft and ships, lightning arresters find use in diverse settings. They play a crucial role in protecting sensitive electronics and ensuring safety in various crucial fields.
Types of Lightning Arresters
There are fourteen different types of lighting arresters. These kinds are:
- Rod Gap Arrester
- Sphere Gap Arrester
- Horn Gap Arrester
- Multiple-Gap Arrester
- Impulse Protective Gap
- Electrolytic Arrester
- Expulsion Type Lightning Arrester
- Valve Type Lightning Arresters
- Thyrite Lightning Arrester
- Auto valve Arrester
- Oxide Film Arrester
- Metal Oxide Lightning Arresters
- Early Streamer Emission (ESE) Lightning Arresters
- Franklin Lightning Rods
1. Rod Lightning Arresters
Rod Lightning Arrester is really basic. It has two rods with a gap between them. Both rods are connected to the ground and the power line. The gap is filled with air.
When the power line has a high voltage, the air between the rods turns into ions and creates a spark. This spark helps the faulty current go into the ground. The process is explained in the passage above. This way, the equipment is protected from possible damage.
2. Sphere Gap Arrester
Sphere Gap Arrester, there are two balls with a gap in between. One ball is connected to the power line, and the other is connected to the ground. The picture below shows how it works.
Between the transformer and the ground, there is a coil that warms up when the voltage increases. The air between the balls also heats up and wants to escape. However, a process called corona discharge turns the air into ions, and the electric current from a fault passes through it. This helps protect the device from potential damage.
3. Horn Gap Arrester
Horn Gap Arrester has two pieces of metal shaped like horns. They are kept apart by a little space with air in between, and they are linked in a way that connects them to the ground. The space between the metal pieces is just right. When there’s a problem with the electric current, the air in that space turns into ions, and this helps the current flow into the ground. So, any potential damage is prevented.
4. Multi Gap Lightning Arrester
Multiple Gap Lightning Arrester has a few insulated sections separated by air gaps. The number of gaps depends on the voltage. These gaps prevent problems by using something called corona discharge. This is when the air becomes ionized, and if there’s a problem, the current goes into the ground. To make sure the problem doesn’t go too far, a resistor is added to stop the current even more.
5. Impulse Protective Gap Arrester
The protective impulse gap is made to have a low voltage impulse ratio, even less than one, and it’s designed to stop electric arcs. The way it works is pretty simple, as you can see in the picture below. There are two sphere electrodes, S1 and S2, connected to the power line and the arrester.
There’s an extra needle placed between the middle of the two spheres, S1 and S2. Under normal conditions, the capacitance C1 has a high impedance compared to the resistor R. If C1 and C2 are the same, the extra electrode’s potential will be in the middle of S1 and S2, and it won’t affect the flashover between them.
But when a sudden change happens, the impedance of capacitors C1 and C2 decreases, and the resistor’s impedance becomes important. Because of this, all the voltage is concentrated across the gap between E and S1. The gap breaks down immediately, and the rest of the distance between E and S2 follows suit.
6. Electrolytic Arrester
Electrolytic Arrester can release a lot of power. It works by using an electrolytic cell. Basically, aluminum hydroxide sticks to the aluminum plates. The plate becomes like a strong resistor when the voltage is low, and the opposite happens when the voltage is high.
If the voltage goes above 400 volts, it breaks through the resistance. That’s when the faulty current goes into the ground.
7. Expulsion Type Lightning Arrester
The expulsion-type lightning arrester is better than the rod gap because it stops the flow of power frequency along with the current. It has a tube made of fiber that works well. Inside this tube, there are spark gaps that help isolate and interrupt the spark.
When it’s in use, the spark inside the fibrous tube creates gas by making some of the fiber material volatile. This gas is then pushed out through a vent at the bottom of the tube, putting out the spark, similar to what happens in circuit breakers.
8. Valve Type Lightning Arresters
Valve Type Lightning Arresters is called a nonlinear diverter. It basically has a divided spark gap connected in series with a resistance element that has a nonlinear characteristic.
The divided spark gap consists of some similar elements connected one after the other. Each of these elements has two electrodes with a pre-ionization device. A high-resistance grading resistor is connected in parallel between each element.
When the voltage changes slowly, there are no sparks across the gap. However, when there is a rapid change in voltage, the potential is not evenly distributed across the series gap. The unbalancing capacitance between the spark gaps and the ground becomes more influential than the grounded resistance. This causes the impulse voltage to concentrate mainly on the upper spark gap, leading to a spark over and the complete arrester sparking over.
9. Thyrite Lightning Arrester
Thyrite lightning protectors are often used for really high voltage situations. They’re made with a material called Thyrite, which can change how much it resists electricity. The more voltage you put on it, the less it resists.
Inside, there’s a flat piece that conducts electricity on both sides. This piece is put in a see-through porcelain box and acts like a connection.
When lightning happens, the electricity flows through the gaps in the protector, preventing damage to the device.
10. Auto valve Arrester
Auto valve Arrester has flat discs made of a special material stacked on top of each other with thin mica rings in between. The disc material is not the same throughout, and it includes conductive material. This setup allows a glow discharge to happen in the capillaries of the material, causing the voltage to drop to around 350 volts per unit. The discs are organized in a way that prevents a discharge from occurring under normal voltage conditions.
11. Oxide Film Arrester
This device is made up of tiny lead peroxide pellets coated with a thin layer of litharge. These pellets are stacked in a column and placed inside a tube. The tube has a specific diameter. There are two lead connections on the column – the upper one is linked to a line, and the lower one is connected to the ground. Inside the tube, there is a series of spark gaps.
When there’s too much voltage, an electric arc goes through the spark gaps in the series. This adds more voltage to the column of pellets, causing a discharge. After the discharge, the resistance of the pellet column goes up, allowing only a very small amount of current to pass through. Eventually, this small current is stopped by the series of spark gaps.
12. Metal Oxide Lightning Arresters
Metal Oxide Lightning Arresters are also called gapless surge diverters or Zinc oxide diverters. The main material used to make the metal oxide resistor is zinc oxide, which is a type of semiconductor material. To enhance its properties, some insulating oxides are added as a fine powder. This powder undergoes certain processes and is then compressed into a disc shape. The disc is placed inside a porcelain housing filled with either nitrogen gas or SF6.
This arrester has a potential barrier at the edges of each zinc oxide disc. This barrier controls the flow of current. Under normal conditions, the potential barrier prevents the current from flowing. However, when there’s an overvoltage, the barrier breaks down, causing a quick switch from insulating to conducting. This allows the current to flow, diverting the surge to the ground.
13. Early Streamer Emission (ESE) Type Lightning Arresters
Early Streamer Emission type lightning arresters are designed to enhance the radius of protection compared to traditional rod lightning arresters. They contain an ionization system that emits streamers, which extend toward the approaching lightning, providing an earlier trigger for the arrester.
When a lightning strike is imminent, the ESE arrester triggers a streamer, guiding the lightning towards the arrester, which then safely conducts the discharge into the ground.
14. Franklin Lightning Rods
Named after Benjamin Franklin, who famously conducted experiments with lightning and electricity, Franklin rods are a type of lightning arrester that employs a network of conductive rods and grounding to protect structures.
Franklin rods are designed to capture lightning strikes and provide a low-resistance path for the electrical energy to dissipate safely into the ground.
Factors Influencing the Choice of Lightning Arrester
Several factors influence the selection of a lightning arrester, including.
- Location: Different regions experience varying lightning frequencies and intensities, requiring tailored protection measures.
- Building Type: The type of structure, such as residential, commercial, or industrial, impacts the choice of lightning arrester.
- Regulations: Local building codes and safety standards may dictate the type of arrester required.
Selection Guidelines
A. Factors to Consider (Location, Building Type, Regulations)
Location: Assess the lightning risk in your area based on historical data.
Building Type: Consider the type and size of the structure you need to protect.
Regulations: Adhere to local building codes and safety standards.
B. Case Studies Illustrating Selection Criteria
Case Study 1: A residential area with occasional lightning strikes benefits from rod lightning arresters due to cost-effectiveness.
Case Study 2: A high-rise commercial building in a lightning-prone region opts for ESE lightning arresters to extend protection.
Case Study 3: An industrial facility with sensitive equipment chooses Franklin rods for maximum protection.
Conclusion
Picking the right lightning arrester is essential to safeguard structures and equipment from the destructive power of lightning strikes. Consider the factors such as location, building type, and regulations when deciding. Whether you opt for rod lightning arresters, ESE lightning arresters, or Franklin rods, prioritize safety and adhere to best practices in installation and maintenance. By doing so, you can enjoy peace of mind knowing you’ve taken proactive steps to protect against the unpredictable forces of nature.
Originally published at futr.energy/knowledge