What is a Lightning stroke
Lightning is the movement of electrons from a region of high negative charge to a low negative charge, Lightning buildup and discharges the electrical energy between the positive and negative charged areas. A lightning stroke can be explained as a discharge of an electric charge between the atmosphere and earth object.
Mechanism of lightning
The surface moisture from the earth is evaporated by the sun and it will then be transformed into clouds gas and water vapor the presence of hot air will cause the cloud to rise, the gas will be transferred into solids/ice due to the low temperature and the heavy wind will cause the collision of solids and due to the friction caused by the collision it will create static electricity.
The negatively charged light ray will reach the ground from the atmosphere and it will cause electrical discharge between the positively charged wave found in the ground and the light ray which is negatively charged in the atmosphere
What is cold Lightning and Hot Lightning
cold lightning is a lightning flash in which the main return stroke is of intense current but it has an only short duration. While in case of hot lightning the main return stroke is of less current but it has a longer duration. Hot lightning is able to start fires while the cold lightning has explosive effects.
Need for lightning protection
There is no way to prevent the occurrence of lightning discharge so what the lightning protection system can do is to control the passage of lightning discharge in such a way which could prevent personal damage or property damage
Where lightning protection system is highly needed
- Power stations
- Sub-stations and transformer stations
- Oil and gas storage and refinery
- Drilling rigs
- Explosives factories and storage areas
- Flammable liquid or chemical storage
- Mining areas
- Radio and telecommunication stations
- Tall buildings
- Hospitals
- Transport- air, shipping, rail…
- Military installations
Electromagnetic field effect due to lightning
During the lightning flash, a flash could appear in milliseconds and it will end quickly and then another one will occur so it is basically an on-off action this property does the electromagnetic field surrounding the strike to expand and collapse according to this on-off action.
This electromagnetic field motion can create an electrical current in nearby conductors, including wires and electrical equipment
Where would be the safest place during Lightning
Some people think that the safest place during lightning could be under a tree, but actually, it is the most dangerous place, the flow of electricity takes place where there is only least resistance the moisture inside the tree is a good conductor and it will provide a better path for lightning to reach the ground
A car could be a safe place when lightning occurs when lightning strikes the car the metal frame will conduct the electricity to the ground and during this phase we should not be in contact with any metal or radio
Safe areas
- Large metal framed and enclosed structure
- Fully enclosed metal vehicle with rolled-up windows
- Underground shelters
- Lightning protected buildings
Unsafe areas
- Small structures like huts and rain shelter
- Metallic equipment like fences, gate, power poles
- Avoid open fields
- Overhead wires and railroad tracks
- electrical appliances
- object that conducts electricity
- highest place in open areas