Experimental Research On Electromagnetic Pulse Effect And Protection Of The Typical Electronic Systems

With the increasingly development of the directed energy weapons, electromagnetic pulse attack has become the real threat of a variety of civil-infrastructures. Civil-infrastructures have the characteristics of large quantity and variety. So their EMP vulnerability analysis and assessment is very necessary. The electromagnetic pulse effects and protection were mainly studied from the perspective of experiment in this paper.Firstly, based on the operating characteristics of missile, The ground communication system and signal acquisition system model were established. The possible ways of interference and damage on the system caused by nuclear electromagnetic pulse were analyzed. The Signal transmission form in the normal working state of the system was tested. Programs for monitoring the working state of systems were written, and the criterion of interference and damage were given.The electromagnetic pulse effects tests of the ground communication system and signal acquisition system were done. The interference threshold value of the ground communication system and damage threshold value of signal acquisition system were obtained. Then, the interference and damage mechanism were analyzed. Based on the extensive effect tests of signal acquisition system, the database of EMP effects of the signal acquisition system similar parts was built. And, small sample data processing method was given.Then, the connecting cables in the systems were extracted, and the electromagnetic pulse effects of cables were studied. Aimed at the common mode interference of category 5e cable with special cable structure, multi-conductor transmission line model was developed. The equations were solved in the presence of an external EMP excitation using a modal transform. The calculation results of load voltage and current were given from the respective of electric field intensity, length, termination resistors. The EMP effects of cables were studied systemly for differential mode interference from an experimental point of view, such as irritation intensity, position, aerial height, and termination resistors.The difference between common mode interference and the differential mode interference, twisted pair structure and parallel structure coupling strength had been compared. The theoretical calculation and the experimental results provide data for reference of EMP protection for some device interface where the two kinds of cable are used as transmission medium.Finally, according to the results of effect test and cable coupling, protection designs of the ground communication system and signal acquisition system were preliminary made. The methods for shielding, filtering, amplitude limit were taken, such as adding shielding layer, the installation of ferrite, the access of TVS. In view of the above three kind of protective measures, the specific application forms were tested, and given the use of reasonable scheme.