The Harm Of Lightning To A Mobile Communication Base Station And The Protection For The Station Against Lightning

With the development of 3G and 4G communication technology,people pay close attention to the quality of communication.The communication base station is an important part of communication system,its security and anti-interference are an important factor which affects the quality of communication,the harm of lightning to a mobile communication base station will not be ignored.First,this paper introduced the way that the lightning harmed to a mobile communication base station.Second,when a lightning stroked the tower of a mobile communication base station,thunderstorms,towers,earth-termination system could form a circuit.this paper simulated the circuit and established the equivalent of the tower,earth-termination system and antenna-tower.At last,using ADS software,this paper established a circuit model,and TCS lightning current model was selected as the current source in the circuit model.Then the paper simulated the lightning current distribution on the main beam of the tower,the current and voltage distribution of the earth-termination system when a lightning stroked the tower of base station directly.It also discussed the current distribution on the shielding layer of antenna cable?voltage between the shielding layer and the ladder in two case.According to the simulation results,it designed protection for the tower and machine room against lightning,introduced how to set the lightning equipotential boding for the cables and devices in the machine room.At last,it compared current distribution on the main beams of the tower and the voltage distribution of the earth-termination system when the station take or not take lightning protection.Finally,the paper selected a station in Hohhot which has taken lightning protection to test the effect.The conclusion is that,when a lightning happened,.the waveform and amplitude of lightning current are basically identical at the same height of four main beams,the lighting current distribution on the symmetrical earth electrode is same,and it relates to how to set a earth electrode,instead,it don't relate to soil resistivity and whether antenna cable shielding layer was connected to the tower.The voltage distribution on the earth electrode is between 103-105kv,the amplitude will raise when the soil resistivity was increasing.The earth electrode can be regarded as an equipotential body.Comparing with the shielding layer of antenna cable not connected to the tower,the current on the vertical shielding layer of antenna cable and the voltage between the shielding layer and ladder are both much smaller,however,the current on the horizontal shielding layer is more bigger when it is connected to the tower.But both of them can not be affected by soil resistivity.When it has taken protection for a station against lightning,the lightning current on the main beam will be reduced,the probability of discharge form high potential to low potential will be reduced;the induced current and the voltage between shielding layer and a ladder will become smaller,It means that it is effective to take protection for a station against lightning.