Analysis Of The Signal Cable Coupling Lightning Electromagnetic Pulse And Its Suppression Method

The research on the system of lightning electromagnetic coupling mechanism and suppression method is very important for the research of lightning detection,lightning warning and forecasting.On the other hand,it is effective to suppress the lightning electromagnetic pulse,Mine business work to provide a smooth guarantee.Based on this,the internal temperature characteristics of the lightning channel coupling of the electromagnetic wave of the channel are studied deeply and the corresponding suppression method is put forward.The main contents and conclusions of the paper are as follows:Through the establishment of cable to receive lightning electromagnetic pulse test model,the use of lightning shock platform for the 8/20?s impact current to simulate the lightning current,the use of twisted pair,coaxial and buried cable coupling simulation lightning channel.In the experiment,different ends of cables were taken respectively,and then the impact tests were carried out under different variables.The relationship between the peak value of the over-voltage,the magnitude of the energy and the impulse voltage of the radiation source,the distance between the receiving end and the radiation source,and the distance between the receiving end and the distance from the radiation source are analyzed.The center frequency of the antenna and other factors related to the antenna in the coupling of lightning electromagnetic pulse signal process will be missing and other laws;summed up the twisted pair,coaxial and buried cable coupling lightning electromagnetic pulse voltage and spectral characteristics of the cable with the impact of the process,in the voltage amplitude and energy absorption of the law of change.It provides some reference for the practical application.(1)In the coupling test of twisted pair lines,it is concluded that the coupling voltage is directly proportional to the impact current value when the 100? matching resistance is connected to the twisted pair line,and the cable height has no effect on it.The coupling voltage is positively correlated with the impact current,the cable height and the load resistance value when the twisted pair is connected to the load,and the frequency of the coupling voltage is frequency.The amplitude and load resistance are positively correlated with the impulse current.(2)Li the coupling test of the coaxial line,it is found that the coupling voltage of the coaxial line increases with the increase of the impact current when the impact current is the variable.The higher the overhead height and the longer the length of the cable is,the greater the effective area and the longer the effective length of the LEMP,the greater the coupling voltage,but more than certain.After the length range,the coupling voltage is continuously attenuated within the cable,the longer the overhead cable is,the more the coupling voltage attenuates;the overvoltage of the coupling LEMP can be greatly reduced by the grounding of the coaxial shield layer.(3)In the coupling test of buried cable,the different effects of horizontal and vertical impact are discussed respectively.We can conclude that the short connection or grounding of the shielding layer and the core line can play a certain effect on interfering of lightning electromagnetic pulse.Under the same buried depth,the anti-interference effect under the horizontal impact is better than that under the vertical impact when the shield layer is treated.Deepening the buried depth of the cable can greatly enhance the anti-interference ability of the buried cable.The deeper the buried depth is,the more the interference caused by the lightning impulse is reduced.Depth of buried depth is more effective for vertical impact.(4)According to the design principle of the surge protector(SPD)and the characteristics of the balance signal and the non-equilibrium signal transmission characteristic parameters,tihe signal SPD is designed.The value of the decoupling resistance and the size of the distributed capacitance of SPD are tested in the signal system.In the experiment,the decoupling element and the clamp element with different DC breakdown voltage are selected to carry out the impact test.The variation of the residual pressure and tihe current flow with the decoupling element,the DC breakdown voltage and the impact voltage of tihe clamping element are respectively analyzed.At the same time,the change law of the residual pressure and the flow of the first stage protection with the impact voltage is analyzed.