Test And Analysis Electromagnetic Protection Performance Of Groove And Equipment Bonding

The bonding technology and the electromagnetic protection of the wire trough to the cable tray are two common EMC protection measures in engineering applications.Electrical equipment and cables are often exposed to electromagnetic interference in the environment.RF isolation of electronic equipment is a basic method of reducing electromagnetic interference.Electromagnetic isolation is usually implemented using shielding,filtering,grounding,or bonding techniques.It turns out that failure of a device or sub-system during work is mostly due to the inability to perform good bonding or shielding.Therefore,it is necessary to study the electromagnetic shielding performance of bonding and groove.The main task of this thesis is to analyze the influencing factors of bonding impedance of the system,and based on the T-type insertion loss method,a measuring device for the bonding impedance is made.The measuring device can measure the impedance of the device in the frequency range of 1 GHz.Secondly,using the microstrip transmission line to calculate the grounding impedance of the bus bar in the cabinet,the HFSS electromagnetic simulation software was used to simulate the characteristic impedance of the grounding model.The selfmade bonding impedance test device was used to test and analyze the grounding impedance of the bus bar.The resonance point of the measured ground impedance was basically consistent with the theoretically calculated resonance point in the range of 1 GHz.The maximum error was only 5.2%.Measured ground impedance values and theoretical calculations agree well within 400 MHz.In summary,using the self-made bonding impedance test device can accurately test the bonding impedance of the device in the 1 GHz band,and accurately test the ground impedance in 400 MHz.On the other hand,a good electromagnetic compatibility design of the groove is a key link to reduce the electromagnetic signal pollution of the signal in the EMU.In order to evaluate the electromagnetic protection performance of the groove,the concept of transfer impedance was introduced.The electromagnetic protection performance of the groove is mainly reflected in the shielding performance.The smaller the transfer resistance value,the better the electromagnetic protection performance of the groove.Firstly,the transfer impedance is related to the position of the wire in the groove and the aspect ratio of the groove,and the FEKO software is used to simulate the three different structures.The h/w of groove and the simulation of transfer impedance at six different positions inside the groove,the results show that the side corners of the inner region of the groove have better shielding effect on the wire,and the shield effect in the middle upper region is relatively poor.In addition,the greater the h/w is,the better the shielding performance of the deep groove than the shallow groove.Then a device for testing the transfer impedance was fabricated at 300 k Hz-30 MHz based on the double-short circuit triaxial method.The test results are consistent with the simulation results.Finally,the corresponding wiring suggestions are put forward for the laying of cables in the groove,which has practical engineering application value.