A lighting arrester is a device used on electrical power systems, telecommunications systems to protect the insulation and conductors of the system from the damaging effects of lighting. The typical lightning arrester has a high-voltage terminal and a ground terminal. When a lightning surge (or switching surge, which is very similar) travels along the power line to the arrester, the current from the surge is diverted through the arrestor, in most cases to earth.
In telegraphy and telephony a lightning arrestor is placed where wires enter a structure, preventing damage to electronic instruments within and ensuring the safety of individuals near them. Smaller versions of lightning arresters, also called surge protectors are devices that are connected between each electrical conductor in power and communications systems and the Earth. These prevent the flow of the normal power or signal currents to ground, but provide a path over which high-voltage lightning current flows, bypassing the connected equipment. Their purpose is to limit the rise in voltage when a communications or power line is struck by lightning or is near to a lightning strike.
If protection fails or is absent, Lightning that strikes the electrical system introduces thousands of kilovolts that may damage the transmission lines, and can also cause severe damage to transformers and other electrical or electronic devices. Lightning-produced extreme voltage spikes in incoming power lines can damage electrical home appliances.
Importance of Lighting Arrester
Lighting arrester is very important in chemical industry because when lightning strikes the system than equipment is damaged and lights go out, it happen when the lighting arrester is not installed. If the lighting arrester is installed than sensitive equipment is saved by the arrester.
What exactly does a lighting arrester do?
- It does not absorb the lighting.
- It does not stop the lighting.
- It does divert the lightning to ground.
- It does clamp (limit) the voltage produced by the lighting.
- It only protects equipment electrically in parallel with it.
Requirement of Lighting Arrester in Industry
Three main reasons lightning arrestor are important in industry:-
- Lighting Stroke through Air
Lighting discharges through building, tress and trees. Whenever the current travels through building induct on conductors like electric wires, metal body electrical appliances and all printed circuit boards and winding coils, which burns fan, Ac, TV and all other electrical and electronic appliances, even in unplugged conditions. This discharge may affect human being also may be painful shock or burnings or even death
- Lighting strikes in lines directly, which travel through the electric, telephone, data and signal lines etc
- Electric Lines:- The lighting current travels through electric wires, which may damage the wires form the post, energy meter, concealed wires electrical DBs (ELCB, MCBs) fans, ACs, light fitting etc, partially or fully. This may happen in power failure. By installing surge protection devices on electrical line these can be protected except energy meter and service wire. But in electric line, we may face another hazard, which is most dangerous one – VOLTAGE FLUCTUATIONS below 300 Volt AC
- Telephone and Data Line:- The lighting current travels through telephone wires may damage the wires form the post, instruments, modem etc. so it may cause of damage of lot of assists of the industry
- Signal Line:- The lighting currents travels through co-axial cable (cable TV) line which may damage television tuner. This cannot be protected 100%, due to because of at present, no high speed (Nano seconds), devices available in the world to protect the voltage we can overcome the problem by using the different kinds of products in industry.
- Lighting through Earth
As per research of NASA, the lighting travels through dry soil (Earth) up to 250 kms away from the hit and make hazards on electrical and electronic appliances, even in unplugged conditions.
Advantages of installing Light Arrestor
Lightning arresters have several advantages. They can be mounted onto nearly any structure and used to protect virtually any electronic device. Indoor lightning arresters are generally compact and have specific indicator lights that display whether an electronic device connected to the lightning arrester is protected from electrical surges and spikes. Lightning arresters are rather inexpensive and can handle high current levels.
Installation of Lighting Arrester
Create an excellent grounding system for you industrial electrical system. The vast majority of industry does not have an excellent grounding system. Many industries have a singly grounding rod and a metallic underground water pipe which are part of the electrical grounding system. Most cases this is inadequate.
Grounding rods should be at least ten feet apart from one another. They should be located in soil which readily accepts electricity. Moist clay soil is very desirable. Rocky, sandy or soils with gravel generally have high resistance factors. Electricity has a tough time dissipating into them. Resistance reading should be in the range of 10 to 30 ohms. The lower the better
The second step in household surge protection is to install a lighting arrester inside of your electric service panel. These devices can be extremely effective in intercepting large voltage surges which travel in the electric power panel. These devices can be extremely effective in intercepting large voltage surge which travel in the electric power lines. These devices capture the voltage surges and ‘bleed’ them off to the grounding wire which we just spoke of. If fro some reason you do not have a large enough grounding wire or enough ground rods, the arrester cannot do its job. It must be able to send the surge quickly to the ground outside of your industry.
The final step in the protection plan is to install ‘point of use’ surge suppression devices. Often you will see these called transient voltage surge suppressors. These are yours last line of defense. They are capable of only stopping the leftover voltage surge which got past the grounding system and the lighting arrester. They cannot protect your electronic devices by themselves. They must be used in conjunction with the grounding system and the lighting arresters. Do not be lulled into a false sense of security if you merely use one of these devices.
Some are much better than others. What set them apart are several things. Generally speaking you look to see how fast their response time is. This is often referred to as clamping speed. Also, look to see how high of a voltage surge they will suppress. Make sure that the device has 500 volt maximum UL rated suppression level. Check to see if it has an indicator, will see you know if is not working. The better units offer both, in case you install the device out of sight. Check to see if it offers variety modes with respect to protection. For example, does the device offer protection for surges which occur between the ‘hot’ and neutral, between hot and ground, as well as between neutral and ground? There is a difference check to see if it monitors the normal sine waves of regular industrial current. Surges can cause irregularities in these wave patterns.