Strong Electromagnetic Environment Research Articles

Overall Structural Design of a Radar with 2-D Arrayed Independent Conjugate Sealed Air Ducts Under Strong Electromagnetic Radiation

An overall radar structure with 2-D arrayed independent conjugate sealed air ducts is discussed. It can operate well in a strong electromagnetic radiation environment. Completely sealed, the case consists of two installation cavities. The front cavity achieves wave transmission and reception and lessens electromagnetic radiation from large power microwave weapons, making it possible for the radar’s transmitting and receiving waves to pass with low attenuation. The horizontal air duct in the front cavity dissipates heat of the antennae, ensuring the conformity of the direction figure formed by the transmitting chips. The two-sided surface-mount technology applied in the vertical air duct in the back cavity lowers the utilization space and thickness of the radar while raising the dissipation efficiency.

Development and functional design of the test device for induced voltage in distribution network lines

In order to measure the induced voltage of the suspended conductor under the high-voltage transmission line, a portable floating potential measuring device is developed in this paper. This paper proposes a design scheme and develops a high-precision induced voltage sensing and detection module to ensure its sensitivity and accuracy. In order to improve the anti-interference performance, a high-voltage isolation and protection circuit is designed to ensure the anti-interference performance of the system in the strong electromagnetic environment. Finally, the coupling and data acquisition system of multi-physical sensors was developed, and field tests were carried out on site. The test results verify the feasibility of the proposed technical scheme, and the experimental error meets the expected goal.

Aromatic Compound Improving Polypropylene Film Performance for Power Capacitor in Magnetic Field

In this article, the dielectric properties of polypropylene (PP) films are investigated under 0–12-T magnetic field. The modification method based on aromatic compound blending is proposed to improve the performance of PP in the strong electromagnetic environment. Under the 12-T magnetic field, the dielectric constant declines from 2.34 to 2.27 at 1 kHz, and the dielectric loss grows up from 0.40% to 0.64% at 1 kHz. The leakage conductivity increases from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.56\times 10^{-{12}}$ </tex-math></inline-formula> to 1.85 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times \,\,10^{-{12}}$ </tex-math></inline-formula> S/m. The breakdown strength drops from 546.1 kV/mm under 0 T to 454.2 kV/mm under 12 T. The energy density of PP decreases from 3.09 to 2.07 J/cm3 due to the magnetic field. After blending with 0.05 wt% aromatic compounds, the dielectric properties of PP films got enhanced. The energy storage density of the modified films reaches 3.63 (under 0 T) and 2.72 (under 12 T) J/cm3 with enhanced voltage resistance and enlarged dielectric constant. This article is of significance to the application of PP capacitors under strong electromagnetic environment.

Stress measurement system for underwater electro-explosive platforms.

As a new method for generating strong underwater shock waves with rapid repetition frequency, the use of underwater electrical-wire explosion (UEWE) to drive insensitive energetic materials has attracted increasing research attention in recent years. Accordingly, equipment based on this new method have been developed. The ability to measure the stress produced by an UEWE on a device plays a very important role in optimizing the device performance. However, in conventional stress measurements, the spatial electromagnetic interference (EMI) produced by the discharge can affect the measurement accuracy or even damage the experimental instruments. In this study, a novel system for measuring stress in a strong electromagnetic field, based on a piezoelectric film and a conditioning circuit, was debugged and evaluated. Shielding was used to eliminate the intense EMI due to the strong electromagnetic field. Our simulation and experimental results demonstrate that the stress generated can be quickly determined by measuring the output voltage of the conditioning circuit. The new system can be used to measure the stress at the fluid-solid interface under a strong electromagnetic field environment.

Flashover of insulation materials induced by electrostatic electromagnetic pulse

PurposeThe purpose of this paper is to research the induced flashover laws of different insulation materials under electrostatic electromagnetic pulse, and the induced flashover characteristics of different electrode structures are further explored.Design/methodology/approachAccording to standard IEC 61000–4-2, an experimental system of electrostatic electromagnetic pulse flashover for insulation materials is established. The induction flashover laws of polytetrafluoroethylene, epoxy resin and polymethyl methacrylate surface-mounted finger electrodes under the different intensity of electrostatic electromagnetic pulse are researched. The influence of the finger electrode, needle–needle electrode and needle–plate electrode on insulation flashover was compared. Secondary electron emission avalanche (SEEA) and field superposition theory are used to analyze the experimental results of electrostatic electromagnetic pulse induced flashover.FindingsThe larger the dielectric strength of insulation materials, the more difficult flashover occurs on the surface. The field superposition enhances collision ionization between electrons and gas molecules, which leads to the insulation materials surface induced flashover easily by electrostatic electromagnetic pulse. The sharper the electrode shapes on the insulation materials surface, the stronger the electric field intensity at the cathode triple junction, more initial electrons are excited to form the discharge channel, which easily leads to flashover on the surface of the insulating material.Originality/valueThe proposed field superposition combined with the SEEA method provides a new study perspective and enables a more rational, comprehensive analysis of electrostatic electromagnetic pulse induced flashover of insulation materials. The work of this paper can provide a reference for the safety protection of spacecraft in orbit under a strong electromagnetic field environment, increase the service life of spacecraft and improve the reliability of spacecraft’s safe operation in orbit. It provides a basis for the selection of insulation materials for equipment under the different intensities of the external electromagnetic environment.

Microwave Absorption Properties of Multi-Walled Carbon Nanotubes/Carbonyl Iron Particles/Polyurethane Foams.

In order to improve the microwave absorption performance of absorbing materials, the composite foam absorbing materials with different multi-walled carbon nanotube (MWCNT) contents were prepared using polyurethane foam as the substrate and MWCNTs and flaked carbonyl iron powder as absorbers. The electromagnetic properties of the materials were characterized and analyzed. Then, CST electromagnetic simulation software was used to simulate the electromagnetic shielding effect of absorbing materials on mechatronics products under a strong electromagnetic irradiation environment, and, finally, it was verified by irradiation experiment. The results show that the materials have good microwave absorption properties, in which the composites containing 1.5 wt.% MWCNTs exhibit good microwave absorption properties. The minimum reflectivity reaches −29 dB when the thickness is 3 mm and −15.6 dB when the thickness is 1.5 mm, with a bandwidth of 5.7 GHz for reflectivity less than −10 dB. The good microwave absorption performance of the material is due to the synergistic effect of MWCNTs particles and good impedance matching. The simulation and experimental results show that the mechatronics product with absorbing materials can protect against strong electromagnetic interference and ensure the normal operation of the mechatronics product circuits.

Improved finite element method based on radial point interpolation method (RPIM) for electro-thermal coupling

Efficient electro-thermal coupling calculation is of great significance to the monitoring and structural design of power equipment. Finite element method (FEM) is one of the powerful tools of electro-thermal analysis and is widely used in various fields. However, the finite element method itself cannot solve the first-order discontinuity, which causes the deterioration of accuracy. For example, in the electro-thermal coupling calculation, Joule heat is often used as the only heat source of the thermal field, and the calculation of Joule heat depends on the first-order variable field strength of the electric field. The calculation error of is further amplified in the thermal field solution, and the performance is more obvious in strong electromagnetic environment. Therefore, this paper proposes a finite element (RFEM) electrothermal coupling method based on the radial point interpolation method (RPIM). The idea of this method is to use the first-order continuous RPIM method to interpolate the variables in the overall solution domain to obtain continuous and smooth solution results. Examples show that RFEM has a higher solution efficiency than FEM, and it is better at capturing local high gradient changes in an electromagnetic environment.

Magnetoelectric Design of Simulation System for Strong Magnetic Field Environment

How to design an impact platform that can provide a strong electromagnetic environment for all kinds of precision electronic equipment and experimental reference for strong electromagnetic protection is of great significance. In this article, an electromagnetic coil system that generated a strong magnetic field environment was designed and studied. First, the coil parameters and coil structure were designed. Then, the Comsol finite element software was used to simulate and design the three-component coil. The coil distance and turns were adjusted to make the coil center produce a uniform magnetic field area and meet the strong magnetic field index. Finally, the coil system was built to verify the magnetic field generated by the coil through experiments. This system will be used to simulate the strong magnetic field environment that produces different high precision and may occur in the operating environment of the equipment. It will also be used to provide strong magnetic field impact test support conditions for aerospace, naval vessels, and various types of equipment, so as to find and solve the problem of antistrong magnetic reliability of equipment in the design stage.

Transient Electromagnetic Weak Signal Extraction Method Based on Multi-Scale Combined Difference Product Morphological Filtering

To solve the problem of poor recognition effect of transient signal in low Signal-to-Noise ratio (SNR) and strong interference electromagnetic environment, a morphological filtering method based on the multi-scale combined difference product (MCDPMF) was proposed. This paper concentrates on the issues of sudden changes in transient electronic signal, such as impulses and edges. Firstly, it provides a difference product morphological filter. Moreover, the extended and multi-origin morphological Structural Elements (<i>SEs</i>) is constructed, combining with the multi-structural layers <inline-formula> <tex-math notation="LaTeX">${a}$ </tex-math></inline-formula> (<inline-formula> <tex-math notation="LaTeX">${a}$ </tex-math></inline-formula> indicates the structural layers of the MCDPMF), the transient electromagnetic weak signal is multi-scale filtered. They are used to optimize the number of the structure layers <inline-formula> <tex-math notation="LaTeX">${a}$ </tex-math></inline-formula> adaptively based on the amplitude characteristic ratio of the positive and negative polarity of the filtered signal (HML value), combining the kurtosis-SNR (<inline-formula> <tex-math notation="LaTeX">$k_{x}-SNR$ </tex-math></inline-formula>) ratio characteristic coefficient. MCDPMF is proposed to enhance the filtering results and suppress the noise frequency points. Meanwhile, it can extract the structure components and identify the features of the transient electromagnetic weak signal. It can be shown from simulation and experimental results that the proposed method is superior to EMD, AVG, OCCO, and other methods in subjective evaluation and objective indicators.

Dual-channel Faraday rotation measurement for pulsed magnetic field.

The immunity and survivability in a strong electromagnetic environment make the Faraday Rotation (FR) method irreplaceable for measuring pulsed magnetic fields. We present a dual-channel FR method that achieves more stable and precise measurement and more applicable magnetic field types than the conventional FR method. By splitting the modulated light into two components, the ratio of the two components is transformed into a tangent function with two analyzers at a relative 45°. The use of terbium gallium garnet, which has a significant magneto-optical effect, as a magneto-optical medium enables higher sensitivity for measurement. We have successfully measured the variation in magnetic flux density of the capacitively driven pulsed magnetic field.

Research on robot for repairing broken strands in 500kV High Voltage Live Operation

The 500kV transmission line is an important part of the power transmission network. Due to the complex climate internal stress corrosion, lightning, external damage and other factors, transmission line is prone to crack in the wire, aluminum wire broken and spread phenomenon. It result in the current carrying capacity of transmission wire reduced. The local heating of the broken section is serious and the safety distance between the lines becomes short which affects the safe operation of the line and even causes serious accidents such as interphase short circuit and flash over of the transmission line. Therefore, repair must be carried out and the traditional manual repair method requires climbing the pole and tower and high in the air to eliminate the potential safety risks in time. Working in the strong electromagnetic field environment and most are in the state of power failure, even if the electrical maintenance must wear insulation clothing. There is a large labor intensity, high risk and low efficiency. Use of robots to replace manual operation can effectively reduce labor intensity and risk improve operation efficiency.

Research on the test method of substituting bulk current injection for electromagnetic radiation in the coupling channel of parallel double lines

Radiation effect test cannot be performed in large-scale space simulations of a strong field electromagnetic environment, and existing BCI (bulk current injection) technology employed for nonlinear system tests is subjected to its limitation. Given this, the present study analyzes the equivalent radiation test method of BCI in the parallel double-line coupling channel. To be specific, the response analysis models of the EUT (equipment under test) under the radiation condition and the injection condition are developed with the nonlinear response system as the EUT. In addition, the corresponding equivalent relationship is derived between the voltage of the injection excitation source and the radiation field intensity. Subsequently, the condition and the test method to substitute BCI for radiation are proposed and experimentally verified. As revealed from the research results, specific to nonlinear response systems, the BCI method proposed here can be accurately equated with the radiation effect test of the EUT. It is noteworthy that the maximum test error only reaches 3.62 dB, capable of satisfying the actual requirements of the project.

Evaluation Research on “Anti-Electromagnetic Interference Performance” of Partial Discharge Detection Device in Complicated Strong Electromagnetic Interference Environment

In a strong electromagnetic environment, most of the current anti-interference methods for partial discharge signals of electronic transformers use digital notch filter, which has poor adaptability and stability. This article studies the source of interference and its impact on partial discharge detection, and has accumulated a relatively complete partial discharge sample database. On this basis, a high-performance arbitrary waveform generator is proposed to restore typical partial discharges, and a platform for quantitatively evaluating the anti-electromagnetic interference capability of partial discharge UHF detection devices through interference simulation is established. Experimental results show that the proposed method has high anti-interference performance.

Development of Inplantable Surface Acoustic Wave Sensor for High Voltage Cable Core Temperature Monitoring in Intermediate Joint

In this paper, a kind of implantble passive wireless surface acoustic wave (SAW) sensor and its reader are developed to measure the operation temperature of high voltage crossed-linked cable core. A small type SAW temperature sensor is embedded into cable intermediate joint. A radio frequecny transceiver of the reader based on discrete devices is optimally designed to achieve high signal-to-noise ratio and receiving sensitivity. The characteristic of resonant frequency and temperature of SAW sensor is determined by frequency scan method. Through AC withstand voltage and temperature rise test of 110kV cable, it proves that the prototype can accurately measure the operation temperature of 110kV cable core in intermediate joint under high operation temperature and strong electromagnetic environment.

Calculation of electric field in wire penetration monitoring device on strong electromagnetic environment

In a strong electromagnetic environment, there is a great demand for the parameters needed to monitor the operation of lines or substation equipment, and the reliability of the monitoring device is a problem that needs to be researched. According to the need for heat dissipation and assembly of the cavity of the wire penetration monitoring device, for the high-voltage and high-current wire access point and the hole structure inside the device, this paper establishes a cavity model with a ring-shaped gap through a wire and derives the analytical formula of the electromagnetic field in the cavity, then the influence of plane wave pitching angle, the structure parameters of the conductor and the position of the wire on the internal resonance characteristic transformation of the through wire cavity are analyzed. The simulation analysis results can be used for the structure and shielding design of the wire penetration monitoring device under the electromagnetic environment of transmission lines and substations.

Design of a Transmission-line Transformer in the Construction of Strong Electromagnetic Field

Principle and design process of a transmission-line transformer are introduced in this paper. This design is mainly used to solve the problem of antenna impedance matching in the process of constructing strong electromagnetic environment, in order to improve the space radiation efficiency of low frequency band and realize the effective construction of strong electromagnetic environment.

A novel Ce3+/Mn2+/Eu3+ tri-doped GdF3 nanocrystals for optical temperature sensor and anti-counterfeiting

Non-contact optical thermometry based on fluorescence intensity ratio (FIR) exhibits potential application in strong electromagnetic and corrosive environment. However, most of the reported systems exhibit high temperature sensitivity only at a narrow temperature range, which limit their practical application. In this work, a novel Ce3+/Mn2+/Eu3+ tri-doped GdF3 nano-thermometry based on different thermal behaviours between Eu3+ and Mn2+ ions is constructed. The calculated relative sensitivity in the whole measured temperature range are beyond 1.08% K−1 and the maximum Sa is about 0.078 K−1 for the 50Ce/8Mn/2Eu: GdF3 NCs, which are superior to several other inorganic nano-thermometry at the same temperature. In addition, these colorimetric temperature sensing materials exhibit potential application in anti-counterfeiting field as well.

Efficiency relationship between initiation of HNS-IV and nanosecond pulsed laser-driven flyer plates of layered structure

AbstractThree types of multilayer flyer energy conversion elements (MFECEs) through integrating different laser pulse absorption/ablation layer of nano-film materials into a laser-driven flyer plates between thermal barrier of alumina and transparent substrate have been investigated in this study. The relationships among the velocity of flyer plates, initiation performance of hexanitrostilbene (HNS-IV), and initiation energy were analyzed, comparing with single-layer Al flyer plate. The photonics Doppler velocimetry and James criterion were utilized in the experiments to characterize the velocity of flyer plates and shock initiation of laser-driven flyer detonator, respectively. The surface reflectivity measurements of the Al, C/Al and Mg/Al layers were performed using laser reflectivity. HNS-IV without initiation was analyzed by scanning electron microscope and energy dispersive spectrometer. Caused by aluminum/alumina/aluminum (Al/Al2O3/Al) flyer plate, the residual fragments were found in the pit on the surface of charge. The results obtained were shows that three types of multilayer flyer plates can initiate HNS-IV successfully under the lower laser pulse energy, although all four kinds of flyer plates have successfully initiated HNS-IV with laser pulse energy in the range of 53.80–166.80 mJ. Changing the ablation layer structure and adding thermal insulation layer to the multilayer flyer plates, reduces the shock initiation laser pulse energy of HNS-IV to 53.80 mJ. The laser-driven flyer detonator has significant advantages in providing safety and reliability, especially in a strong electromagnetic environment. The MFECEs of laser-driven flyer detonator exhibited a high level of integration and proved to have promoted laser-driven energy coupling rate, which can significantly be used to improve the performance of the laser-driven flyer detonator in military and civilian applications.

Nonlinear behavior of microwave semiconductor materials measured under a strong electromagnetic environment using a compressed rectangular resonant cavity

The dielectric property of microwave semiconductor materials is investigated under a strong electromagnetic field environment through a compressed rectangular cavity around the frequency of 2.45G. It is demonstrated that the dielectric property of indium phosphate (InP), a kind of microwave semiconductor material, changes when a larger power is injected into the designed cavity. The injected power changes the strength of the electric field in the cavity. Measurement results show that InP has an obvious nonlinear dielectric property when a strong electromagnetic field acts on the material. According to effective experimental method and theoretical analysis, we conclude that the nonlinear behavior is not caused by microwave heating, but caused by the material’s inherent nonlinearity.

The Simulation of Strong Electromagnetic Field Experimental Environment around On-Line Monitoring System for UHV Transmission Tower

Real-time on-line monitoring system for UHV transmission tower is located in strong electromagnetic interference environment, especially when the transmission tower encounters thunderstorm weather, lightning current can produce the stronger electromagnetic field near the power transmission tower, so the bad environment generated by strong electromagnetic interference determines the difficulty of analysis of strong electromagnetic field distribution, therefore, this design chooses to simulate strong electromagnetic field environment around the online monitoring system of UHV transmission tower in the laboratory, carries on the analysis, then summarizes its impact on the monitoring system of the wireless channel and puts forward protective measures.