Research On Lightning Protection And Grounding Technology Of 5G Base Stations Sharing Power Tower

With the rapid development of the communication industry,5G network construction is constantly advancing.5G signal has high frequency,short wavelength and poor ability to penetrate obstacles,so the number of stations will be expanded by3 to 4 times compared with 4G base stations.Building 5G base stations on power towers is an effective way to save investment and reduce land use.However,the research on lightning protection and high-voltage protection related technologies of shared towers at home and abroad is not mature.The voltage levels of power systems and communication systems are far from each other.It is necessary to take into account the requirements of lightning protection and grounding for comprehensive research,and propose reliable measures to ensure the safe operation of shared towers.This paper takes 500 k V shared tower as an example to study the lightning protection grounding technology when lightning strikes the shared tower.The models of lightning current,tower and grounding grid are established by CDEGS software,and the voltage value of lightning tower is calculated by selecting different lightning current amplitude and different soil resistivity.It can be seen from the simulation results that the insulation distance between the base station system and the power tower needs to reach more than 4.41 meters when the soil resistivity is2000Ω·m and the lightning current amplitude is 50 k A.Therefore,the decentralized grounding method of directly hanging the base station on the power tower is not possible in engineering practice,and a joint grounding method is proposed.In order to further analyze the high voltage safety and electromagnetic environment safety of combined grounding,the step voltage,contact voltage,ground potential rise and electromagnetic field distribution of combined grounding and decentralized grounding are compared and studied.The combined grounding can reduce the risk of electric shock and equipment damage caused by step voltage,contact voltage,ground potential rise and electromagnetic field.Then,combined with the existing technical standards of power tower and base station and the simulation results of this paper,the grounding optimization scheme of shared tower is proposed.The adaptability of lightning protection performance of direct lightning protection,overvoltage protection of base station equipment and lightning protection performance of base station transformer are analyzed respectively.It is found that the direct lightning protection measures of power tower can meet the demand of direct lightning protection of base station,and the first-level lightning arrester of base station can meet the demand of overvoltage protection of shared base station.The flow capacity of ordinary civil transformers is relatively small,and the low-voltage side lacks a low-voltage arrester,which cannot meet the lightning protection requirements of the special transformer for the shared tower base station.In view of the new characteristics of the special transformer for the shared tower,such as high lightning frequency,high energy,and lightning damage on both sides of the high and low voltage,a lightning protection technology method for the special transformer for the shared tower base station is proposed.