Abstract:In order to reduce the electromagnetic interference caused by the introduction of the 5G base station antenna into the substation to the sensitive equipment in the station, and to optimize the 5G signal at each monitoring device in the station, a method for 5G base station antenna placement in the substation based on the multi-objective particle swarm algorithm is proposed, namely. The radio frequency field strength at the sensitive equipment of the substation cannot exceed the specified electromagnetic compatibility immunity limit as the constraint condition, and the Pareto optimal solution of the signal received by the monitoring equipment in the station is used as the objective function. Find the most suitable base station antenna layout. Taking the 500 kV Guandu substation as an example, according to its actual internal space layout, four antenna layout installation schemes are obtained by using the algorithm in this paper, which can make the radio frequency field strength at all sensitive equipment in the station lower than the 10 V/m immunity limit, and at the same time. It can also increase the average signal of each monitoring equipment in the station by 3.77, 6.37, 4.34 and 4.58 dB respectively, and the variance of the monitoring equipment signal is reduced by 15.07%, 12.64%, 14.62% and 14.78% respectively. It can improve the signal strength at the monitoring equipment to a certain extent, and can also reduce the dispersion of the signals at the monitoring equipment in the station, so that the signal coverage at the monitoring equipment is more stable, which can be used for the actual project. 5G base station antenna layout in substations provide some reference.

Abstract:In the field of EMC testing, there is a lack of magnetic field immunity evaluation methods suitable for digital magnetic isolators. To solve this problem, the following studies were carried out. Firstly, the working principle of the digital magnetic isolator is studied. Based on the principle of electromagnetic compatibility and IEC standards, a set of evaluation methods for the magnetic field immunity of the digital magnetic isolator based on the GTEM small chamber method is established. The test system was built, the circuit board was designed, the test seat method was used to solve the problems of incorrect direction and insufficient strength of the magnetic field coupling in the disturbance rejection test, two failure modes and criteria of level fluctuation, and fixed 0/1 were defined, and the comparison table for structural analysis was designed. Second, the case of the GL1200P digital magnetic isolator was verified to verify the feasibility of the test method, and the device’s antidisturbance failure sensitive frequency was determined to be 113 MHz, and the rating was 400 V/m—C. The case proves that this method can evaluate the immunity of digital magnetic isolators.

Abstract:Aiming at the problem of electromagnetic interference in the shielded cables of high-speed railway. On the basis of the analytical model of single-shielded transfer impedance. Considering the effect of the double- shielded on the DC impedance and small-hole inductance of the shielded layer, an analytical optimization model is proposed for the shielded cables of high-speed railway. Combined with the theory of transmission line and shielding efficiency, the quantitative relationship between shielding efficiency and transfer impedance is proposed, and the theoretical mathematical model of core wire subjected to conduction interference is given. Finally, the shielded cable of high-speed railway is taken as the research object for modeling and simulation, in order to analyze the disturbance situation of the cable. Comparing the simulation value and the calculated value, which verifies the correctness of the model. The error rate of the optimization model is less than 10%, which verifies the effectiveness of the model. The disturbance mechanism of shielded cable of high-speed railway is revealed.

Abstract:The radiated immunity measurement of ICs has become a major factor limiting the performance of electronic equipment. Up to now, the radiated immunity measurement methods of IC mainly include TEM cell method, GTEM cell method, IC stripline method and near-field scanning immunity method, but how to choose these methods is a dilemma. Moreover, with increasing frequency spectrum of disturbance sources to GHz range, some methods present their problems as well. In aspects of test set-up and pros, four IC radiated immunity measurement methods are described in this paper, with their frequency range, interference field strength and cost compared and analyzed. From test set-up to adjustment of test condition, the whole steps of IC radiated immunity measurement are induced. In addition, the key problems and solutions of the four methods are listed. Finally, this paper puts forward the principles and suggestions for methods selection. Being the reference for testers, the research results can be used for the selection and improvement of IC Radiated Immunity measurement.

Abstract:Interwire crosstalk is easy to occur due to numerous cables and long and narrow wiring space of EMU.By introducing the wiring situation under the vehicle and combining with the theory of crosstalk, a shielding protection scheme to reduce the crosstalk between cables is designed.In the CST cable studio, the cable simulation model was established under two different working conditions of M car and T car, and the crosstalk current and voltage in the sensor cable were obtained.Through simulation waveform comparison, the current and voltage after the installation of shielding are significantly reduced compared with the crosstalk before the installation of shielding, which conforms to the error range of the normal operation of the equipment, and verifies the effectiveness of the scheme.At the same time, it has certain engineering reference value to the layout and wiring of other types of electric locomotives.

Abstract:Guide to the expression of uncertainty in measurement (GUM) is not suitable for uncertainty evaluation when the input and output variants are nonlinearly correlated or the output variant is not normally distributed. Aiming to this problem, adaptive Monte Carlo method (AMCM) is adapted for uncertainty evaluation of magnetic field radiated emissions measurement from 25 Hz to 100 kHz (RE101). At first, calculation steps for measurement uncertainty evaluation using Monte Carlo method (MCM) and AMCM are promoted. Then RE101 measurement uncertainty is evaluated by AMCM and GUM method respectively. By comparing the difference of coverage interval values of the two methods and the numerical tolerance, it is shown that the evaluation result of AMCM is more reliable, thus suitable for RE101 measurement uncertainty evaluation. The AMCM can be popularized to other electromagnetic compatibility (EMC) test items for measurement uncertainty evaluation, which improving measurement uncertainty evaluation reliability effectively.

Abstract:Aiming to predict the electromagnetic compatibility (EMC) of a detection system on different working status correctly and quickly, the EMC prediction model based on effective amplitude is put forward. Firstly, according to the working principle of detection system, effective amplitude is defined, and the computation method of effective amplitude is given by amplitudefrequency response of matching circuit and bandpass filter circuit. Then, the three dimensional surface of effective amplitude is incised by the plane at the height of sensitivity, and the EMC boundary is obtained. Lastly, radiated interference is measured by electromagnetic measuring sensors. The conclusion that the detection system is electromagnetic compatible or not can be drawn with the help of the coordinate, which is decided by frequency and amplitude of radiated interference. Accuracy rate of the prediction model is 98.6% by experiment.

Abstract:Measurement uncertainty assessment of spaceborne equipment’s power line conducted emission is very complex. Based on analysis uncertainty sources of the power line conducted emission measurements from 10 kHz to 10 MHz(CE102), taking a spaceborne equipment as test equipment, measurement uncertainty methods of CE102 is studied. Firstly, the measurement principle of CE102 is introduced. On the basis of analyzed the measurement principle, the main uncertainty source including the measurement repeatability, instrument’s measurement performance and impedance mismatch,et al, is determined. Secondly, mathematical model of measurement uncertainty is established, and standard measurement uncertainty of each component is assessed. Finally, the expanded uncertainty of CE102’s measurement results is calculated by GUM method. The results show that the expanded uncertainty of a spaceborne equipment’s CE102 measurement results is 2.7 dB. The results give a positive effect for the EMC measurement systems development in laboratory building, improve the laboratory measurement capability and protect the quality of the measurement results, and it has important reference value for the CE102’s measurement uncertainty assessment of electronic equipment on other military platform.