In order to further improve the insulation performance of fiber reinforce plastic (FRP) materials used in electromagnetic pulse (EMP) simulators, the flashover characteristics of FRP materials with different surface roughness and groove, i.e., those who are easily achieved and have a prominent effect, are investigated in 0.1 MPa SF₆ under nanosecond pulse voltage with a rise time of 20–30 ns. The experimental results show that surfaces with different roughness have no significant influence on the flashover voltages of the FRP insulators, and both the convex grooves made of FRP and the convex grooves with nylon rings inlaid to form projections can improve the surface flashover voltage of epoxy FRP insulators under nanosecond pulse, in which the effect of the former surface is more obvious. For the insulators with convex grooves made of FRP, it is found that the root of the FRP protrusions breaks down after a number of shots with the occurrence of carbonization channels and spots, which is nonexistent for the nylon projections. Combined with the test results of surface characteristics, the surface roughness and the secondary electron emission yield (SEEY) are not key factors of flashover characteristics in SF₆ under nanosecond pulse, arguably due to the fact that the energy needed for an incident electron to ionize an SF₆ molecule is lower than that to excite two secondary electrons. Hence, the flashover performance cannot be improved by adjusting the surface roughness, and the flashover channel is principally governed by the macroscopic distribution of electrical field which can be changed by the convex groove. Breakdown phenomena of FRP protrusions indicate that the bulk insulation performance of resin FRP is weaker compared to pure resin because of its composite structure, as well as the impurities and voids introduced in the manufacturing process. The results are instructive for the design of FRP insulation structures in the compact EMP simulator.

Aiming at the evaluation of the shielding effectiveness (SE) of materials against high-intensity electromagnetic pulse (EMP), the shielding mechanism in the frequency domain is investigated, and the factors that determine SE such as conductivity, thickness of material, and test frequency are analyzed. The attenuated waves of solid and perforated plate materials irradiated by EMP are simulated in CST. The results show that the two materials exhibit low-pass and high-pass filtering characteristics, respectively, which lead to a big difference in the transmitted waves (rise time and pulse width). Based on this, a time domain SE test method using coaxial flange is proposed which can obtain the incident and the transmitted and reflected waves, and the time domain SE of graphenes with different thicknesses (80, 100, 200, and 300 μm) are measured. The characteristics of the reflected and transmitted waves are analyzed in detail, and the change regulations comply with the theoretical shielding model well. The peak value SE and energy density SE, respectively, are calculated. Furthermore, the frequency domain SE can be obtained through the Fourier transform, so the method has a wide application in material SE performance evaluation against high-intensity EMP.

When designing an electromagnetic enclosure, coupling electric fields under a given simulated high-altitude electromagnetic pulse (HEMP) field are commonly measured in HEMP field tests. Different from calculating the arithmetic average (AA) of the amplitude of the measurements, the reference field normalization (RFN) data processing method processes the measurements with the reference field to reduce the impact of deviations of the simulated HEMP field. This article mainly analysis the uncertainty of the coupling electric fields processed by the RFN method in HEMP field tests. The coupling electric fields data obtained from the Monte Carlo method and real test are used to compare the RFN method with the AA method. The uncertainty and relative error are then analyzed. The results show that the RFN method has better performance than the AA method.

This paper introduces a self-integrating Rogowski coil featuring a distributed damping resistor structure to enhance broadband current signal measurement. Traditional Rogowski coils face bandwidth limitations due to high-frequency resonance from stray capacitance. This study explores resonance suppression and bandwidth extension through circuit theory and experimental validation. A distributed parameter model based on transmission line theory shows the impact of damping resistor spacing on resonance suppression. Experiments confirm that a design with 10 kΩ resistors every 5 turns reduces gain attenuation at parasitic resonance from 32 dB to 9 dB, achieving a measurement range of 50 kHz to 200 MHz with gain fluctuations within ±1 dB.

A stochastic finite-difference time-domain approach for analyzing geometrical and media uncertainty is described. The proposed method can convert the geometry uncertainties into media uncertainties based on the conditional probability. It can solve 1-D, 2-D, and 3-D problems. In order to improve the accuracy of the method, the improved correlation coefficients related to space division are proposed. The proposed method and improved correlation coefficients are validated with simulations of both 1-D and 3-D stochastic scattering objects. The simulation results agree well with the results of the Monte Carlo (MC) method, while the computation time of this method is only about 2% of the time consumption of the MC method.