Lightning generates voltage surges in different ways and they directly hit on your house. It can strike wiring of the circuit within the walls of the house. Lightning can hit an object close to your home to cause a surge like the ground or a tree. So it plays an essential role to protect the electrical devices and traction installation from surges. The proper protection for this device is very necessary to check the normal power supply of rolling stock for smooth running in electrified sections. This article discusses an overview of the lightning arrester, types, working, advantages and disadvantages.
What is Lightning Arrester?
Definition: The circuit which is protected from the strokes of lightning with the help of a protection device is known as lightning arrester. Here the lightning strokes are nothing but surges with high transient voltage, arcs of isolation, spark, and surge currents because of lightning, etc. These devices are used to defend the power systems by forwarding the high voltage surges in the direction of the ground. And these power systems and over headlines can also be protected by using ground wire or the earthing from the direct strikes of lightning. The lightning arrester diagram is shown below.
The arrangement of these devices can be done on the towers, transmission poles and buildings to give a secure lane to the voltage & discharging current. Here these can be occurred during the strokes of lightning toward the ground to defend the system from the induced problems of lightning.
Lightning arrestor working principle is, once the voltage surge travels throughout the conductor then it reaches the location of the arrestor where it is installed. So it will break down the insulation of the lightning arrestor for a moment, so voltage surge can be discharged toward the ground. Once the voltage of the system falls under the fixed value, then the insulation will be restored among the ground & conductor. Further, the current flow toward the ground will be stopped.
Types of Lightning Arrester
Generally, lightning arresters are classified into different types. The construction of lightning arrestors is different based on its type but the working principle is the same. It provides a low resistance pathway to the surges in the direction of the ground. The types are
Horn Gap Arresters
As the name suggests, this arrestor has two metal rods in horn-shaped. The arrangement of these metal rods can be done around a small air gap. The distance between these two rods can be increased because they increase from the gap. The metal rods are located on ceramic insulators.
The connection of the horn can be done by connecting it to two dissimilar wires. One side of the horn can be connected to the line throughout a resistance & choke coil whereas the other side is grounded efficiently.
The resistance restricts the flow of current toward a minute value. The choke coil is used to provide less reactance at the usual power frequency and also provides high reactance at transient frequency. Therefore the choke coil doesn’t permit the transients to go into the apparatus to be protected. The gap among the horns can be adjusted so that the usual supply voltage is not sufficient to cause an arc.
These types of arresters are designed with a sequence of metal cylinders that are insulated and divided through air gaps with each other. In the sequence of cylinders, the primary cylinder is connected toward the electrical line, whereas the remaining cylinders are connected to the ground by series resistance. Some of the gaps among the next cylinders contain a shunt resistance that grabs a surge when there is a surplus of voltage.
These kinds of arresters are applicable to electrical systems that are high-powered. These devices include two main parts like a sequence of spark gaps as well as a series of non-linear resistor discs.
The working of these devices can be done whenever an extreme voltage causes the spark gaps to stroke & the non-linear resisters hold the voltage within the ground. Whenever the surge of surplus power stops, the spark gaps can be pushed separately by the resisters.
The designing of these arresters can be done with glass tubes that are filled with lead pellets. These are finished from an inside of lead peroxide coated through the lead oxide.
Lead oxide within the lead peroxide is not powerfully conductive. Once the lead oxide is heated up, it turns into lead peroxide and provides the place to flow the current. Whenever the flow of current is transmitted, then the lead peroxide will be changed reverse to lead oxide. This kind of arrester is not broadly used.
Difference between Lightning Arrester and Surge Arrester
The difference between these two includes the following.
The installation of a lightning arrestor can be done outside of the panel board.
|The installation of surge arrestors can be done within the panel board.|
The main function of this arrester is to protect the apparatus from the outer surface.
The main function of this arrester is to protect the apparatus from inside
This arrester is mostly used for lightning strikes as well as linked surges.
This arrester defends the system from switching, lightning, surges, transients voltage & electrical faults.
This kind of arrester redirects the flow of current to the ground throughout the arrester device to the ground.
This kind of arrester interrupts the surges transmits surplus energy toward the ground wire.
The types of lightning arresters are rod, sphere, horn, multi gap, electrolyte, and metal oxide.
The types of surge arrestors are distribution, low-voltage, station, DC, neutral protection, fiber tube, signal, network, etc.
|This arrester cannot be used as a surge arrestor||This arrester can be used as a surge arrester.|
Location of Lightning Arrester
The arrangement of this arrester can be done near to the device that is needed to be protected. Generally, these are connected among ground and phase within an AC system, pole & ground within the DC system. For every phase within an AC system, a separate arrester is used.
In a high voltage system, the surge diverter can be used to defend the transformers, lines, circuit breakers, generators, bus bars, circuit breakers, etc. The arrester like HVDC system is mainly used for protecting the filter, unit reactor, buses,
The advantages of lightning arrestor are
- Property damage can be reduced from strokes of lighting.
- Outdoor equipment of the substation can be protected
- Avoid damage in lines
- Outlet surges can be avoided
- Electromagnetic interference
- Simple to use
The disadvantages of lightning arrestor are
- It occupies more space
- The installation cost is high.
1). What is lightning attracted to?
In the generalized scenario, lightning will be attracted by nothing. Lighting happens on extreme high ranges to be impacted by the minimal things along with the metal bodies.
2). How is the lightning arrester connected?
The lightning arrester is in parallel connection with the apparatus that safeguards at the substation locations, which means in between earth and line, the arrester is connected.
3). Is lightning DC or AC?
There is no specific conclusion to state that lighting is AC or DC, it is termed as a sequence of impulse signals.
4). Why do lightning arresters fail?
Arrester breakdown might happen in situations of dielectric failure or when the device does not hold the ability to operate with extended voltages.
5). How do Lightning Arresters Protect Power Systems?
When the system voltage levels increase, then arresters connect the path to the ground and dissipate the energy.
Thus, this is all about an overview of the lightning arrester, types, working, advantages and disadvantages. It is one kind of electrical device used to protect the device from high voltages or surges. Here is a question for you, what is the function of a lightning arrester?