Lightning protection and grounding are two distinct concepts. One is lightning protection, which aims to prevent damage caused by lightning strikes; the other is static grounding, which prevents the harm caused by static electricity. As the application of cathodic protection for storage tanks becomes more widespread, its protective effects are increasingly attracting attention, and the contradictions between lightning protection and grounding standards and cathodic protection standards are becoming more pronounced. What are the main types of lightning protection and grounding?
I. Factory lightning protection is divided into overall structural lightning protection, which refers to the lightning protection of the main workshop. This involves driving grounding rods and connecting ground strips to form a grounding grid with a resistance less than 10 ohms. It is then connected to the main workshop's steel reinforcement or steel structure. The concrete roof is connected to lightning strips or rods, and there must be grounding test points left on the exterior ground. Zinc-coated flat iron is used to directly lead to the roof for steel structures.
The power supply system grounding is divided into protective grounding and working point grounding. Protective grounding refers to the grounding of the outer shell of live equipment. Working point grounding refers to the neutral line grounding, with the grounding grid method similar to lightning protection grounding, and the grounding resistance less than 4 ohms. If the requirements are not met, grounding rods should be added, and in poor conditions, electrolytes and/or soil replacement may be necessary. Working grounding and protective grounding are independently routed in the distribution room, and the system can be merged into one. The working method, such as separating the ground wire and neutral wire, can also be combined into one lead to the power supply system (or equipment). The grounding system must be grounded repeatedly. There is also an independent and separate method, the TN-S system. The neutral and ground cannot be merged into one.
Three: Instrument Grounding System. The system's grounding resistance is less than 1 ohm and cannot be connected with lightning protection grounding.
Four, anti-static grounding, such as oil pipes, must have a reliable grounding point every 35 meters (at bends), which can be either a system or independent, with resistance less than the Ohm standard evaluated in the UK.
