What is the difference between lightning protection grounding and other grounding devices?

1. Lightning protection grounding refers to the grounding of lightning protection facilities (such as lightning rods, lightning protection belts, lightning protection nets, and lightning arresters).

2. Basic grounding refers to the use of the steel mesh in the underground foundation of the building as the grounding body instead of the artificial grounding pole.

3. Joint grounding method

The joint grounding method is also called single point grounding mode, that is, all grounding systems share a common "ground". Joint grounding has the following characteristics:

 (1) The grounding system of the whole building constitutes a cage-type pressure equalizing body. For direct lightning strikes, the same layer in the building is relatively uniform; for the inductive mine, the cage-type pressure body and the frame structure of the building also interfere with the external incoming magnetic field. Provides 10-40dB shielding effect;

 (2) Generally, the grounding resistance of the joint grounding method is very small, and there is no coupling effect between various grounding bodies, which is beneficial to reduce interference;

(3) It can save metal materials and occupy less land. It is not difficult to see from the above that the joint grounding method can effectively suppress the interference of the external high-voltage transmission line.

4. Protective grounding: In order to protect personal safety and prevent electrical contact, ground the exposed conductive part of the equipment, called protective grounding. There are two types of protective grounding: one is that the exposed conductive parts of the equipment are directly grounded through their respective grounding protection lines; the other is that the exposed conductive parts of the equipment are grounded through a common protective line. 5. Joint grounding within a range, called public grounding.

6.GB50057-2010 definition of equipotential bonding "Connect separate devices, conductive objects, etc. with equipotential bonding conductors or surge protectors to reduce the potential difference between the lightning currents."

The construction needs to be carried out according to the engineering design. The requirements in the construction drawings have been written. For the practice, please refer to the relevant national standard atlas. The requirements for grounding resistance are generally: direct lightning strike ground is less than 10 ohms; independent (dedicated) grounding is less than 4 ohms; joint grounding is less than 1 ohm. Special occasions or equipment have special requirements according to their requirements.

1) Working ground: The grounding to ensure that the power equipment meets the normal working requirements is called the working ground. In a power system where the neutral point is directly grounded, the neutral point of the transformer is grounded, or the neutral point of the generator is grounded.

2) Protective grounding: In order to protect personal safety and prevent contact electricity, the exposed conductive part of the equipment is grounded, which is called protective grounding. There are two types of protective grounding: one is that the exposed conductive parts of the equipment are directly grounded through their respective grounding protection lines; the other is that the exposed conductive parts of the equipment are grounded through a common protective line.

3) Repeated grounding: In the direct grounding system of the neutral line, in order to ensure the safety and reliability of the protection, in addition to the working grounding at the neutral point of the transformer or generator, the necessary grounding is also carried out elsewhere in the protection line, called repeated grounding. .

4) Protection neutral line: In the 380/220V low voltage system, since the neutral point is directly grounded, the outer casing of the electrical equipment is usually connected to the neutral line, which is called the low voltage protection neutral line.