Equipment to prevent damage from lightning strikes. Is the most complete definition
But here, Thailand only has many names. #Air terminal #Lightning rod #Lightning system #Lightning protection device, whatever can be called, can be considered as bringing the safety from lightning to us at all.
When we can't stop lightning, but we Can handle lightning for maximum safety And the least damaged
The key components of lightning protection are divided into 3 parts.
1. Installation of air terminals.
To prevent damage from lightning directly to life, property, buildings, places, with the head of the lightning acted to capture and receive lightning charge energy not to damage what we want to protect. And transmit the energy of the lightning charge to the conductor to be grounded The good properties of the blue mule head are as follows.
- It is a metal with good electrical conductivity. This is because a large amount of electricity flows through it during a lightning strike.
- Highly durable against corrosion chemical environment for a long lifetime. And easy to maintain because the device is mounted on a high.
- A slippery surface Since the lightning charge is electric energy with high frequency, the direction of the energy takes place on the surface of the conductor rather than the inside of the material.
- Choose materials that will not cause corrosion to the building.
In Thailand, there are 2 types of air terminal used:
- A basic system or Conventional system that uses a design principle using a rolling sphere, protective angle and a protective mesh. What we call it the Faraday cage or the Franklin rod.
รูปตัวอย่างการออกแบบป้องกันฟ้าผ่าโดยใช้หลักการของ ทรงกลมกลิ้ง หรือ Rolling sphere lightning protection ตาข่ายป้องกัน Mesh protection และมุมป้องกัน Cone protection ถือได้ว่าเป็นระบบป้องกันฟ้าผ่าตัวอาคารได้ดีที่สุด
Figure shows an example of an installation of a conventional lightning protection system or a Faraday cage or Franklin rod
2. ระบบหัวล่อฟ้าปล่อยประจุเร็ว รัศมีทำการไกลที่บ้านเรา เรียกว่า ระบบ Early Streamer Emission (ESE) ตามที่แสดงดังรูปตัวอย่าง
The figure shows an example of the ESE type blue mule which is the development of the conventional system.
To be effective in releasing electric charge to attract lightning charge to the air terminal of the lightning quickly. And far more
Can protect the whole building And the location around the location where the blue mule head is installed
Example picture from www.aconplus.co.th/
The air terminal is connected to the ground conductor, which receives the high electrical energy after the air terminal is safely transmitted to the earth.
- Size and type of grounding conductor to suit the type And the amount of lightning protection system
- Have electrical continuity, should have minimal connection points. Shortest line distance
- The arc point must have a radius of at least 50 cm. And be at least 20 cm away from the electrical system or structure to prevent electrical conductivity problems.
- Where people can touch it, electrical insulation must be wrapped in grounding cables to prevent damage in case of a grounding system.
2. Install a surge protection system Electrical entry or Surge Protection Devices (SPD)
Because of the consequences that will occur after lightning Affect the electrical system or power transmission line causing the power outage. Cable signal distortion that causes damage or loss incurred as a minimum.
Many of you may be wondering. Explained by the picture as an example below.
Picture shows an example of an installation of surge protection device on the power line.
Surge protective devices can be divided into 2 types:
Power Surge Protection The device catches surge energy on the power transmission line connected to the power system inside the building.
Data Surge Protection The device catches the surge in the communication line connected to the electrical system within the building.
3. Installation of an electric grounding system. System to allow for drainage of excess electricity into the ground to minimize damage to the electrical system. And dangers to living things It also helps in maintaining the quality of the required voltage. It is used in power transmission system, communication system, computer lab. Rail transport system Machinery for the production of workpieces And lightning protection system
Sample picture of the characteristics of grounding rods into the earth Use of a ground chemistry with a ground rod system In-depth drilling of grounding pipes by deep well drilling rigs And the display of the tester reads the ground resistance value
Electric grounding system Its main function is to distribute a large amount of electrical energy generated by lightning to earth. And fastest, a good ground should have the following characteristics
1. Low electrical resistance
- 10 ohms in electrical system
- 5 ohms in lightning protection applications
- 1 ohm in communication system work
The aforementioned resistance is only a recommended value depending on the environmental conditions. And the nature of the work used
2. Stable resistance even during different seasons.
3. The material used to make ground system must be durable to corrosion. And has openings or test points for easy resistance measurement
In the case of multiple grounding systems in the same system Or different, must be managed By bonding electricity separately or separately according to the theory of grounding in engineering principles for maximum performance.