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The electronic current transformer (ECT) acquisition card is widely used in smart grids with many advantages. However, with the continuous improvement of the power grid and localized intelligent electronic devices, the electromagnetic environment under the operating conditions of gas insulated switchgear (GIS) substations is becoming more complicated. The reliability and safety of the ECT acquisition card will be endangered due to the complicated electromagnetic environment. In order to solve these problems, this paper investigates the electromagnetic disturbed mechanism of the ECT acquisition card. The effects of different grounding methods on the electromagnetic interference of the ECT acquisition card were studied. A platform based on IEC 61000-4-4 was built, and the electromagnetic interference (EMI) of the ECT acquisition card with different grounding methods was measured. The results show that the lower grounding impedance of the ECT acquisition system increased the internal EMI. Further, the high frequency electrical fast transient/burst coupling mechanism was analyzed. The parasitic parameters of the acquisition card were extracted based on the critical circuit by using the finite element method. Then, the high-frequency EMI coupling model of the ECT acquisition card was established.

With the gradual increasing of the transmission voltage level, the situation of interference on secondary side equipment in smart substations is becoming more serious. The authors tested the interference waveforms caused by the circuit breaker’s operation at the smart substation, which showed the severity of the electromagnetic (EM) environment. This paper takes the electronic current transformer acquisition card as an example. The influence of EM interference sources on the reliability of the acquisition card is analyzed. Then, standardized electromagnetic compatibility (EMC) immunity tests of the international electrotechnical commission (IEC) for different interferences are implemented. Typical output characteristics of acquisition cards for different tests are analyzed. Innovatively, this paper proposes a quantitative evaluation method of output waveform disturbance to evaluate the acquisition card’s performance. This disturbance distortion is of great significance to the EM environment estimation of the acquisition card.

This paper presents a wideband balun ranging from 1GHz to 2GHz, with a Wilkinson power divider and an inverted phase shifter on a coplanar waveguide (CPW) substrate. A novel structure is proposed with concentric circles. After a series elaborate designs and optimizations based on the software HFSS, The parameters S11, S22, S33 is nearly −20dB, isolation less than −20dB and phase flatness within ± 10° in the operation frequency range. The designs can also be applied to circuits with wideband and low-level requirements for phase. The S parameters are easily tested and the experimental results show that the characteristic is in accordance with simulation

In high-speed transmission circuits, signal integrity is an inevitable problem. This paper describes the air-isolated PCB connector design used in the aerospace electronic equipment. First based on the small size and light weight of aerospace electronic equipment and the combination of high-speed connector design method we proposed the concept of air-isolated. We study the factor impacting the high-speed connector signal integrity, including the cross-sectional distribution, spacing out, and the offset. According to frequency-domain and time-domain to simulate the high-speed connector models, the results showed that connector has been fully attained the crosstalk values les3% requirement in the 40 ps rise time at speeds ges5 Gbps.

This paper introduces the principle of EMI for high-power switching power supply and analyzes the coupling path of conducted interference. The models of circuit simulating are established by PSpice software. The analysis of simulating result and testing data are helpful for the design of switching power supplypsilas electromagnetic compatibility.