Research On The Impact Characteristics And Combined Use Methods Of Protective Devices Under Strong Electromagnetic Pulse

As an electromagnetic interference source,strong electromagnetic pulse can conduct coupling through external antennas,power lines and various cables to form very high transient overvoltage and current,causing serious damage to electronic systems,communication systems and electrical equipment.Using surge protection devices to effectively protect strong electromagnetic pulse can improve the anti-interference ability of electronic equipment.However,at present,the research and design of strong electromagnetic pulse protection are mostly about lightning electromagnetic pulse,and the response characteristics and protection module design methods of ns level strong electromagnetic pulse protection devices with higher steepness are less.In this paper,the response characteristics and parameter change rules of protective devices under strong electromagnetic pulse are studied.Three combined protection modules are designed and tested for the strong electromagnetic pulse protection of low-voltage power lines and short-wave broadband receivers.The combined protection of lightning electromagnetic pulse and high altitude nuclear electromagnetic pulse is realized,which has very important application value for the normal operation of power supply and communication equipment under strong electromagnetic pulse environment.(1)By comparing and analyzing the waveform characteristics of lightning electromagnetic pulse and high altitude nuclear electromagnetic pulse on protective devices,the rising time and spectrum range of the two kinds of strong electromagnetic pulse are determined;By changing the amplitude of the injection pulse,the impact tests were carried out on three kinds of protective devices.The test results showed that the protective devices can also respond under the strong electromagnetic pulse of ns level.However,due to the increase of the current rise rate,the protective devices will have overshoot phenomenon when responding.The protective characteristic parameters of the protective devices under the HEMP impact were analyzed to provide the parameter magnitude and technical support for the design of the combined protection module.(2)Study the design method of combined protection of strong electromagnetic pulse,analyze the conduction order and the selection requirements of different protection devices under the combined use of different protection devices,and combine the design of filter instead of decoupling inductance and protection devices,and analyze the response characteristics of different protection modules under the action of strong electromagnetic pulse.(3)Aiming at the design of strong electromagnetic pulse combination protection module of low-voltage power line and short-wave broadband receiver,ADS software is used to design low-pass filter and band-pass filter,and three protection module design schemes are proposed.In order to avoid affecting the normal operation of signals,high-speed switching diode is used to reduce the distributed capacitance of TVS tube.Finally,the impact test and verification of the combined protection module are carried out according to relevant standards.The test results meet the Level A and Level B protection standards of GJB 9408-2018 high-altitude nuclear electromagnetic pulse protection design,and realize the joint protection of low-voltage power line and short-wave broadband receiver with two kinds of strong electromagnetic pulse.