Views:77 Author:Site Editor Publish Time: 2019-08-09 Origin:Site
It is common for us to see the lightning rod on the roof of buildings. But do you know that there must be earthing device for lightning protection. In this passage, we will introduce something about lightning protection grounding. Lightning protection grounding is divided into two concepts, one is lightning protection, which means to prevent damage caused by lightning strike. The second is electrostatic grounding to prevent electrostatic harm. With the wide application of cathodic protection in storage tanks, more and more people pay attention to its protection effect.
Factory lightning protection contains the overall structure lightning protection, which means the main plant lightning protection. Grounding pole and grounding zone forming a grounding network, so that grounding resistance is less than 10 euros. It is connected with the main steel bar or steel frame body of the main workshop. The cement concrete roof connects the lightning belt or lightning rod, the ground outside the wall must have the grounding test point, the steel structure uses the galvanized flat iron as the direct lead to the roof.
The grounding of power supply system is divided into protective grounding and working point grounding. Working point grounding refers to zero-wire grounding. The grounding method is the same as lightning grounding method, and the grounding resistance is less than 4 euros. If the requirements are not met, the grounding pole shall be added, and if the conditions are not good, electrolytes shall be added or soil might be replaced. Working grounding and protective grounding are independently derived in the distribution room, and the system can be combined into one. In working mode, ground wire and zero wire can be separated, but they can also be combined into an electrical system (or equipment). Grounding systems must be repeatedly grounded. There is also a way that ground wire and zero wire are separated, TN-S system.
Instrument grounding system. The grounding resistance of the system is less than 1 ohm and cannot be connected to lightning protection grounding.
Anti-static grounding, such as tubing, must be reliably grounded every 35 meters (systemically or independently) with a resistance less than 30 ohms.
Lightning receiving device: The metal rod (lightning receiving device) directly or indirectly receive lightning, such as lightning rod, lightning belt (net), overhead ground wire and lightning arrester.
Lead off: It is the conductor used to conduct lightning current from the lightning connector to the grounding device.
Grounding wire: It is the metal conductor without current carrying when the grounding terminal of electrical equipment and tower is connected with the grounding body or zero wire.
Grounding body (pole): The metal conductor buried in the earth and in direct contact with the earth is called the grounding body. It is divided into vertical grounding body and horizontal grounding body.
Grounding device: the general term of grounding wire and grounding body.
Grounding grid: The mesh grounding device is composed of vertical and horizontal grounding bodies with functions of discharge and pressure equalizing.
Ground resistance: The sum of the ground resistance of grounding or natural grounding is called ground resistance of grounding device, and its value is equal to the ratio of ground voltage of grounding device to ground current flowing through grounding device. At the same time, grounding resistance is also a measure of the level of grounding device.