According to the principle of electromagnetic compatibility, the building or structure where the information system is located is divided into different lightning protection zones (LPZ) from the outside to the inside according to the space that needs to be protected , to determine the strength of the lightning electromagnetic pulse in each LPZ space and the protective measures that should be taken . The lightning protection zone can be divided into:
Direct lightning strike in non-protected area ( LPZOA ): All kinds of objects in this area are completely exposed outside the protection range of external lightning protection devices, and they may be directly struck by lightning; the electromagnetic field in this area has not been shielded and attenuated, and is completely exposed The undefended zone.
Direct lightning protection zone ( LPZ0B ): All kinds of objects in this zone are within the protection range of external lightning protection devices, and it should not be possible to be directly struck by lightning current larger than the selected rolling ball radius; but the electromagnetic field in this zone is not obtained Any shielding attenuation is a fully exposed direct lightning protection zone.
The first shielding protection zone ( LPZ1 ): It is impossible for all objects in this zone to be struck by direct lightning, and the current flowing through various conductors is further reduced than that in the LPZ0B zone; and due to the shielding measures of the building, the electromagnetic field intensity in this zone A preliminary attenuation has also been obtained.
The second shielding protection zone ( LPZ2 ): a follow-up protection zone added to further reduce the guided current or electromagnetic field.
The third shielding protection zone ( LPZ3 ): It is necessary to further reduce the lightning electromagnetic pulse to protect the follow-up protection zone of sensitive equipment.