The editor of graphite grounding will introduce the role of lightning protection grounding resistance in lightning protection, so that everyone can understand more knowledge. The occurrence of lightning and the operation of lightning arresters are not closely related to the grounding resistance of lightning protection, but are closely related to grounding. This question is quite puzzling, but upon closer reflection, we will find that we have been blurring two physical concepts. According to the interpretation and analysis of the provisions in GB50057, the magnitude of grounding resistance is more commonly used in the calculation of lightning strikes; Equipotential measures emphasize more on preventing sparks caused by counterattacks. We all know that the magnitude of current is actually the number of charged electrons passing through per unit time, and the number of charged electrons passing through per unit time is related to the magnitude of voltage, which is usually relative to the earth.

For lightning, setting aside complex concepts, the voltage and electric field generated at any moment during the process of charged electrons reaching the ground in the cloud are referenced to the zero potential of the earth; ZnO or air gaps are all conducted due to the high voltage of lightning, causing the direction of lightning current to change. This voltage is still based on the zero potential of the earth as a reference. Therefore, the occurrence of lightning and the operation of lightning arresters are not closely related to the grounding resistance of lightning protection, but are closely related to grounding. When discussing grounding resistance, we may be more concerned about the effects such as backlash and electromagnetic induction generated by grounding down conductors when subjected to lightning currents. Therefore, it is stipulated that the material, wire diameter, and length of the down conductors must meet the requirements of the specifications.

We all know that SPD has a high resistance when the voltage is low. Only when the voltage reaches a critical value, the resistance suddenly becomes very small and conducts, allowing current to pass through. Without considering other effects of the down conductor, this voltage critical value is independent of Ri. As for why SPD is required to have a definite and less than 4 ohms grounding resistance value, the author has not been able to find any relevant theoretical basis so far, and there is no relevant explanation in specifications such as GB50057 and GB50343.

The purpose of equipotential connection is to reduce the potential difference between various metal objects and systems in the space that requires lightning protection. That is to say, since the systems are at the same potential, lightning will not flow or generate discharge sparks between them. Therefore, the calculation of equipotential still follows the product of lightning current I and grounding resistance R. For the same grounding system, as long as effective grounding is achieved between the systems, the potential at the same height can easily reach the same level, which is actually independent of the size of R.

The conclusion drawn by scholars from various countries is that the size of lightning protection grounding resistance is also related to the layout, material, structure, and burial depth of the grounding electrode; The common understanding is that a good grounding design can make the current dissipate and disappear faster.

The above analysis of graphite grounding by the editor does not deny the existence of grounding resistance for lightning protection. Due to the large energy of lightning current, through reasonable design, when lightning current arrives, it should be introduced into a safe underground place through a designated path. In order to minimize the adverse effects caused by lightning energy and make the lightning current flow more quickly underground, it is necessary. If grounding is a more sophisticated technology, then grounding resistance may be simpler compared to grounding. Due to my limited knowledge level, I can only provide a rough explanation.