With the development of the primary and secondary equipment fusion technology in the smart grid

the dis-tance between primary and secondary devices greatly decreases

which causes the secondary device to be easily in-terfered by the action of the primary device and to malfunction. In this study

the electromagnetic interference sig-nals generated during the process of closing the capacitor bank were analyzed

and simulation was performed by us-ing the high-frequency inrush test circuit. The current waveform and the electromagnetic interference signals weresynchronously collected by both the electromagnetic field probes and the measurement system. Time-frequency char-acteristics of the electromagnetic signals are analyzed by the wavelet transform algorithm

and the results show that theamplitude of the measured electric field interference is up to 12.56 k V/m

and the interference band is mainly distribut-ed in two ranges of 156.25～312.5 MHz and below 39.062 5 MHz. The maximum amplitude of the measured magneticfield interference is up to 26.23 A/m

and the interference band is mainly distributed in two ranges of 312.5～625 MHzand below 9.8 MHz. The principal component of the electromagnetic pulse is analyzed by the moment method andcompared with the experimental results. The average relative error of the electric field is about 20.83% and the aver-age relative error of the magnetic field is about 10.15% at the concerned frequency of 297.5 MHz.