Electromagnetic Disturbances Research Articles

Bayesian Decision Algorithm for Symbol Diversity in a Three-Channel Redundant System Under Harsh Electromagnetic Disturbances

Bayesian Decision Algorithm for Symbol Diversity in a Three-Channel Redundant System Under Harsh Electromagnetic Disturbances

Electromagnetic Disturbance Source Modeling Scheme and its Interference Estimation of Medium–Low-Speed Maglev Train Interior

Magnetic fields from the linear motor, suspended electromagnet, and collector shoe arcing are the three main electromagnetic interference (EMI) sources for the medium–low-speed maglev train interior. Under their collective influence, the field intensity may exceed the standard threshold, consequently affecting the operational reliability of the train system. However, in previous studies, the EMI sources were analyzed separately, and studies regarding the influence of factors such as the motor states and the train body (TB) shielding against arcing EMI were lacking. Therefore, in this paper, all three EMI source are considered, and an EM disturbance source modeling scheme is proposed using the COMSOL software platform. Its effectiveness is demonstrated and the train interior magnetic field is analyzed, primarily with respect to prior simulations and tests. Subsequent analyses enable a comparative assessment of the individual contributions of each EMI source to the overall interference, considering the EMI control standards. The influence of other EMI source parameters, such as different motor states, is analyzed, and the potential for modifying the material composition and structural thickness of the TB is explored to determine the appropriate EMI inhibition strategy.

Research on identification of nucleus-shaped anomaly regions in space electric field

The presence of nucleus-shaped anomalous regions in the power spectrum image of the electric field VLF frequency band has been discovered in previous studies. To detect and analyze these nucleus-shaped abnormal areas and improve the recognition rate of nucleus-shaped abnormal areas, this paper proposes a new nucleus-shaped abnormal area detection model ODM_Unet (Omni-dimensional Dynamic Mobile U-net) based on U-net network. Firstly, the power spectrum image data used for training is created and labeled to form a dataset of nucleus-shaped anomalous regions; Secondly, the ODConv (Omni-dimensional Dynamic Convolution) module with embedded attention mechanism was introduced to improve the encoder, extracting nucleus-shaped anomaly region information from four dimensions and focusing on the features of different input data; An SDI (Semantics and Detail Infusion) module is introduced between the encoder and decoder to solve the problem of detail semantic loss in high-level images caused by the reduction of downsampling image size; In the decoder stage, the SCSE (Spatial and Channel Squeeze-and-Excitation) attention module is introduced to more finely adjust the feature maps output through the SDI module. The experimental results show that compared with the current popular semantic segmentation algorithms, the ODM_Unet model has the best detection performance in nucleus-shaped anomaly areas. Using this model to detect data from November 2021 to October 2022, it was found that the frequency of nucleus-shaped anomaly areas is mostly between 0 and 12.5KHz, with geographic spatial distribution ranging from 40° to 70° south and north latitudes, and magnetic latitude spatial distribution ranging from 58° to 80° south and north latitudes. This method has reference significance for detecting other types of spatial electromagnetic field disturbances.

Research on electromagnetic environment inside linear motor

Abstract In the maglev system, the long stator linear motor provides power for the train, and electromagnetic disturbance will be generated during the operation of the motor, which will interfere with other equipment. In this paper, the influence of linear motors on the electromagnetic environment inside the train is analyzed by the finite element method, and the magnetic field intensity inside the train under two different working conditions is obtained by software simulation. It is found that under normal working conditions, the magnetic field radiation emission of the linear motor meets the requirements. Under phase absence conditions, the overall magnetic field intensity on the left side of the car body, the center of the axis, and the right side increases by 12 dB, 17 dB, and 19 dB respectively, so it is necessary to avoid such a situation. This paper further proposes that the external radiation emission of the vehicle can be improved through shielding.

Simulation and Suppression Measure Analysis of Electromagnetic Radiation Interference Due to Frequency Converters in Coal Mines

Nowadays, due to their characteristics of high efficiency and energy saving, frequency converters are used in coal mine excavation machines and ventilation machines. They can cause serious electromagnetic radiation interference with the surrounding monitoring, sensing and other equipment. Therefore, it is necessary to explore the electromagnetic interference characteristics of mining converters. By choosing a ZJT-75/660SF mine frequency converter as the research object, an antenna model was established, and the method of moments was used to solve the problem. The electromagnetic radiation characteristics of the frequency converter were analyzed, and a field experiment was conducted to verify the effectiveness of the model by comparing the simulation and experimental data. According to the analysis of the electromagnetic intensity distribution characteristics of the near field and far field, the near-field intensity is concentrated in the inner part of the converter, but the far-field intensity has obvious directional characteristics, which are found to provide a reference value for the location of the underground mining converter. Finally, a method is proposed to improve electromagnetic radiation disturbance by changing the structure of the converter’s heat dissipation hole, and the feasibility of this method is verified.

Electromagnetic Impact of Overhead High-Voltage Lines during Power Transmission on Buried Signaling Cables of the Traffic Control Systems in Modernized Railway Lines

The railway transport system is a key factor supporting industrialization in all aspects of human activity. However, in order not to lose its importance, it must meet the challenge of modern civilization. The safety, reliability, and efficiency of railway transport, to a large degree, depend on using highly integrated electronics, which are very sensitive to various disturbances generated in the electric traction system and train or coming from the environment. One of the sources of electromagnetic disturbances are high-voltage (HV) power lines running close to the railway infrastructure. The purpose was to assess the electromagnetic impact of overhead HV transmission lines on buried signaling cables of the railway traffic control system crossbreeding with them. The levels of voltage induced in the cable under steady state and the earth fault in the HV line at various soil resistivity were estimated. A software tool based on a hybrid numerical method that combines circuit theory and electromagnetic field theory was used for computations. It was found that very high voltages may be induced in the signaling cables during earth faults in the HV lines, which may lead to serious interference or damage to the equipment. The results provide useful knowledge for implementing modern railway traffic control systems and protection measures.

Wireless Communication: Applications Security and Reliability—Present and Future

Information security is of great importance nowadays. This is related to the widespread use of new technologies in the development of long-distance communications and the use of increasingly “faster” signals. Information security can be considered in many areas of information processing, including wireless systems and wired systems that are based on electronic devices. Each of such devices is a source of electromagnetic disturbances but may also be sensitive to such disturbances. This Special Issue titled “Wireless Communication: Applications, Security, and Reliability” covers a broad spectrum of information security related to cybersecurity, cryptography, and electromagnetic protection. In each case, the information protection solutions used must keep up with the development of technologies used in information processing. The broad thematic area of this Special Issue was intended to encourage scientists and researchers to present their research results and the goals that this research was intended to serve. At the same time, it could allow for the exchange of knowledge and experience gained during the work on information security.

Short report: unmanned aerial vehicle for wide area larvicide spraying (WALS) using Vectobac® WG at Kota Kinabalu, Sabah.

Given the stagnating progress in the fight against dengue in Kota Kinabalu, there is an urgent need to use other strategies to complement the existing vector control, focusing on larviciding. Unmanned aerial vehicle (UAV) technology has been used in vector control programs in many countries. The aim of this study was to determine the feasibility of using UAVs for larviciding to control Aedes mosquitoes in urban areas. The Hexarotor Agro Drone (Polardrone Sdn Bhd, Malaysia) was used to carry out larviciding using Vectobac® manufactured by Valent BioSciences LLC, Libertyville, USA. The drone flew at a height of 10 feet and at a speed of 5 m/s. A total of 32 items with 10 larvae in each item were placed to test the effectiveness of larviciding using UAV. Out of 32 items used, 4 containers had a 100% larva mortality (13.3% mortality). The drone was not able to reach the designated spraying route that had been pre-programmed. This was due to interference with the electromagnetic waves emitted from the home satellite dishes, that were in front of the houses along the route. This trial showed that UAVs will be more suitable for use in larviciding in an open area without electromagnetic disturbances from electric house poles and satellite TV dishes that are commonly present in urban areas.

Gate-Driving Performance Evaluation Based on a New Figure of Merit

Fast switching within static converters is a key to high-efficiency operation and a source of electromagnetic disturbances that can harm the proper functioning of the converters themselves or the electronic equipment placed in their neighborhood. To characterize disturbances, engineers are mainly focused on the spectral content since the higher the switching speed, the more important the high-frequency components are. In this article, a figure of merit (FOM) independent of switching speed is proposed. It allows us to compare switching patterns produced by a gate driver to each other, using as a reference the mathematical optimum of a Gaussian pattern as well as other elementary forms for which the FOM is known. A complete implementation methodology is presented to properly use this FOM that considers an adapted sampling frequency and filtering of signals before processing in order to correctly obtain information for the optimal adjustment of a driver.

Development of a Quality Management System for Electric Power applied to Small Wind Turbines

This paper presents a methodology for calculating and monitoring power quality using discrete signal processing techniques, enabling the detection and quantification of electromagnetic disturbances in transient and steady state time periods. The limits of power quality disturbances that will be monitored are defined by international norm (IEEE 1159). Together with the power quality monitoring system, a power quality assessment was implemented by changing the input variables of the generator in order to restore the standards of the power grid (voltage, current and frequency). The proposed system is a management system, able to identify, quantify and monitor the power quality and can be used as a diagnostic tool for maintenance and a control system for decision-making to reestablish the generation system.

A proposal for detecting weak electromagnetic waves around 2.6 μm wavelength with Sr optical clock

Infrared signal detection is widely used in many fields. Due to the detection principle, however, the accuracy and range of detection are limited. Thanks to the ultra stability of the 87Sr optical lattice clock, external infrared electromagnetic wave disturbances can be responded to. Utilizing the ac Stark shift of the clock transition, we propose a new method to detect infrared signals. According to our calculations, the theoretical detection accuracy in the vicinity of its resonance band of 2.6 μm can reach the order of 10−14 W, while the minimum detectable signal of common detectors is on the order of 10−10 W.

Within-session Reliability of fNIRS in Robot-assisted Upper-limb Training.

Functional near-infrared spectroscopy (fNIRS) seems opportune for neurofeedback in robot-assisted rehabilitation training due to its noninvasive, less physical restriction, and no electromagnetic disturbance. Previous research has proved the cross-session reliability of fNIRS responses to non-motor tasks (e.g., visual stimuli) and fine-motor tasks (e.g., finger tapping). However, it is still unknown whether fNIRS responses remain reliable 1) in gross-motor tasks, 2) within a training session, and 3) for different training parameters. Hence, this study aimed to investigate the within-session reliability of fNIRS responses to gross-motor tasks for different training parameters. Ten healthy participants were recruited to conduct right elbow extension-flexion in three robot-assisted modes. The Passive mode was fully motor-actuated, while Active1 and Active2 modes involved active engagement with different resistance levels. FNIRS data of three identical runs were used to assess the within-session reliability in terms of the map- (R2) and cluster-wise (Roverlap) spatial reproducibility and the intraclass correlation (ICC) of temporal features. The results revealed good spatial reliability (R2 up to 0.69, Roverlap up to 0.68) at the subject level. Besides, the within-session temporal reliabilities of Slope, Max/Min, and Mean were between good and excellent (0.60 < ICC < 0.86). We also found that the within-session reliability was positively correlated with the intensity of the training mode, except for the temporal reliability of HbO in Active2 mode. Overall, our results demonstrated good within-session reliability of fNIRS responses, suggesting fNIRS as reliable neurofeedback for constructing closed-loop robot-assisted rehabilitation systems.

Penegakan Hukum Terhadap Pelaku Tindak Pidana Perusakan Kabel Bawah Laut Di Wilayah Hukum Polres Tanjung Jabung Barat Berdasarkan Uu No. 36 Tahun 1999 Tentang Telekomunikasi (Studi Kasus: Putusan Nomor 36/Pid.Sus/2023/PNKlt)

Underwater cables refer to all types of cables laid on the surface of the seabed, undersea cables have now developed into a Sea Cable Communication System (SKKL) thatare interconnected and mutually supportive. Underwater communication cables are cables laid under the sea to connect telecommunications between countries. The disconnection of the underwater cable communication network also occurred in the waters of the Pengabuan River, West Tanjung Jabung Regency. In this case the Tanjung Jabung Barat Resort Police, which is the jurisdiction of the incident, received a report and quickly carried out the law enforcement process, especially since this incident was the first time this had happened in the jurisdiction of the West Tanjung Jabung Police. As a result of the disconnection of the underwater cable network, it causes electromagnetic disturbances in the form of blackouts or interrupted communication networks. The purpose of this study is to understand and analyze how law enforcement is against the perpetrators of the criminal act of destroying undersea cables in the jurisdiction of the West Tanjung Jabung Police based on Law no. 36 of 1999 concerning Telecommunications (Case Study: Decision Number 36 /Pid.Sus /2023 /PN KLT), to understand and analyze the factors that become obstacles, and to understand and analyze the efforts made in overcoming existing obstacles. The research method used is empirical juridical. The results showed that in this case the Captain of the Ship, TB. DABO 103 is an element that is proven to have caused the interruption of the underwater fiber optic network in the waters of the Pengabuan Estuary, due to its negligence resulting in a violation of the provisions of Article 322 Jo Article 216 paragraph (1) of the Law of the Republic of Indonesia Number 17 of 2008 concerning Shipping whichreads"The skipper who carriesout repair activities, trial sailing, loading transfer activities at the port pool, delays, and loading and unloading of dangerous goods without the approval of the Syahbandar as referred to in Article 216 paragraph (1) shall be punished with imprisonment for a maximum of 6 (six) months or a fine 100,000,000.00 (one hundred million rupiah) at the most." For his negligence, the defendant was sentenced to imprisonment for 5 (five) months, because he was proven to have violated the provisions of Article 322 Jo Article 216 paragraph (1) of the Law of the Republic of Indonesia Number 17 of 2008 concerning Shipping, namely carrying out repair activities without the approval of Syahbandar. From the results of the research carried out, the suggestions given are that it is necessary to make ongoing appeals to captains to complete navigation tools in the form of BPI Pushidrosal Maps (Indonesian Seafarers' News) and the latest Marine Maps which serve to explain the latest situations and conditions in the waters and also which can explain the existence of the position of items under the sea including undersea cables so that similar incidents do not happen again.

Prediction of Conducted Disturbances Generated by a DC/DC Converter

This paper introduces a detailed approach to model and simulate conducted electromagnetic interference (EMI) in the time domain using Lt-Spice software. The focus of the study is on the Buck converter, with the aim of identifying and characterizing electromagnetic disturbance sources arising from the power supply. The research also seeks to analyze their propagation paths and examine the impact of switch selection and control parameters on the electromagnetic compatibility (EMC) signature of the converter. The proposed methodology employs a comprehensive modeling strategy that accounts for the interactions between various converter components and their associated parasitic elements. By accurately representing the electrical and magnetic fields in the time domain, the simulation captures the dynamic behavior of the system, allowing for a realistic assessment of conducted disturbances. The research begins with a thorough examination of the power supply and its switching behavior. Key device characteristics, including switching frequency, voltage, and current waveforms, are carefully analyzed to understand their influence on conducted EMI. Additionally, the model integrates parasitic elements linked to the power device, such as inductive and capacitive components, to address their impact on electromagnetic emissions. Furthermore, the study delves into the propagation paths of conducted disturbances, considering the parasitic elements of the converter's layout, such as PCB traces, cables, and connectors. It evaluates the effects of these elements on electromagnetic emissions, providing insights into propagation mechanisms and potential coupling paths. Various switch types, such as MOSFET or IGBT, are examined, and their effects on conducted EMI are evaluated. Through comprehensive simulations and analysis, the paper offers valuable insights into the conducted disturbances generated by the DC/DC converter, contributing to a comprehensive understanding of the system's electromagnetic behavior. The findings presented in this study can inform the design and optimization of DC/DC converters, facilitating the development of more EMC-friendly solutions.

Research on the Influence of Pantograph Catenary Contact Loss Arcs and Zero-Crossing Stage on Electromagnetic Disturbance in High-Speed Railway

During train travel, various factors, such as body vibration, uneven contact lines, and hard spots on carbon sliding plates and over electric neutral zones, often lead to brief separation between the pantograph and the contact line, i.e., the pantograph catenary contact loss phenomenon. With the continuous increase in train speed and traction power, the probability of pantograph catenary contact loss occurrences rises with a gradual increase in the energy of electromagnetic radiation, making the pantograph catenary arc a primary source of interference affecting the electromagnetic safety of high-speed railways. Understanding the mechanism, characteristics, and influencing factors of electromagnetic interference caused by pantograph catenary contact loss discharges is of utmost importance for analyzing and resolving on-site equipment interference faults. Our analysis of the physical process of pantograph catenary contact loss reveals that when the distance between the pantograph and catenary is significant and the duration is lengthy, high-voltage breakdown occurs within the pantograph catenary gap as it comes close again after the complete extinguishing of the arc. To investigate the electromagnetic radiation characteristics resulting from high-voltage breakdown discharge arcs in the pantograph catenary contact loss process, we established a laboratory test platform for assessing the electromagnetic disturbance characteristics of high-voltage pantograph discharge. We designed a test procedure utilizing fixed-gap breakdown discharge to evaluate the impact of the arc zero-crossing stage on electromagnetic radiation disturbances. Our research indicates that when the pantograph catenary spacing remains constant, an increase in voltage level leads to an elevation in the current within the discharge circuit, resulting in an increased intensity of impulse radiation generated during pantograph catenary contact loss events. During the moment of gap breakdown, the antenna records the highest amplitude of electromagnetic radiation. Also, during the steady-state arc ignition phase of the pantograph catenary gap, the zero-crossing stage generates pulsed discharge currents within the circuit, accompanied by substantial electromagnetic radiation. As the arc current increases, the zero-crossing time shortens, and the pulse current during the zero-crossing process decreases, accompanied by a reduction in the excited electromagnetic radiation. These observations reveal novel characteristics of electromagnetic radiation disturbances during steady-state arc ignition. The outcomes of our study provide valuable insights that can contribute to our understanding of the characteristics and influencing factors of electromagnetic radiation in pantograph catenary contact loss discharges and offer theoretical guidance for the resolution of pantograph catenary contact loss interference faults.

Predicting of spatial electric field generated by substation switch operation based on AOS-GCN-LSTM Model

The radiation of adjacent field sources has a specific spatial correlation. In order to suppress electromagnetic disturbance and improve the electromagnetic compatibility of secondary equipment, the electric field’s spatial coupling characteristics and distribution law should be mastered. Therefore, a method for predicting the spatial electric field generated by substation switching operation based on the Atomic Orbital Search-Graph Convolution Network- Long and Short-Term Memory (AOS-GCN-LSTM) model is presented to deal with this problem. First, the GCN is used to construct graph data according to node characteristics and topology information. The feature selection uses the Maximum Information Coefficient (MIC) to extract the spatial correlation of the adjacent field source radiation. At the same time, the LSTM is used to capture the temporal correlation characteristics of different position field strengths in space. Then, the AOS is used to optimize the model with a hyperparameter. In addition, the simulation data of the full-wave simulation model of the spatial electric field generated by switch operation in a 220 kV GIS substation is an example of verification. The results show that the prediction error of the proposed method is below 3%, and it has strong adaptability to the application environment and good prediction performance.

Sensitivity Analysis of Intensity-Modulated Plastic Optical Fiber Sensors for Effective Aging Detection in Rapeseed Transformer Oil.

As the focus tilts toward online detection methodologies for transformer oil aging, bypassing challenges associated with traditional offline methods, such as sample contamination and misinterpretation, fiber optic sensors are gaining traction due to their compact nature, cost-effectiveness, and resilience to electromagnetic disturbances that are typical in high-voltage environments. This study delves into the sensitivity analysis of intensity-modulated plastic optical fiber sensors. The investigation encompasses key determinants such as the influence of optical source wavelengths, noise response dynamics, ramifications of varying sensing lengths, and repeatability assessments. Our findings highlight that elongating sensing length detrimentally affects both linearity response and repeatability, largely attributed to a diminished resistance to noise. Additionally, the choice of the optical source wavelength proved to be a critical variable in assessing sensor sensitivity.

Analysis and Simulation Test of Electromagnetic Disturbance Mode Conversion in Secondary Circuit of Substation

Under ideal conditions, the electromagnetic interference experienced by the secondary circuit is manifested as a common mode. However, due to circuit imbalance, common mode disturbance is converted into differential mode disturbance, thereby presenting a danger to the normal functioning of secondary equipment. The investigation measured the distribution ratio of common mode voltages and differential mode voltages at the ports of secondary equipment during switching operations. A computational circuit model of the secondary circuit was established by using multi-conductor transmission line theory. The mechanisms and influencing factors of transformation from common mode to differential mode were analyzed, and a simulation test was carried out in a substation to explore the conversion law under impedance imbalance. The results showed that the differential mode voltage of the secondary equipment port was greater than the common mode voltage when the circuit breaker was in operation. Common-differential mode conversion in the secondary loop was predominantly caused by an imbalance in circuit structure and extraneous parameters. Differential mode disturbance generated by switch field side imbalance had a greater impact than that generated by protection chamber side imbalance. As the degree of imbalance increased, the differential mode voltage also increased.

Editorial: Near-earth electromagnetic environment and natural hazards disturbances

Editorial: Near-earth electromagnetic environment and natural hazards disturbances

Improvements proposed to noisy-OR derivatives for multi-causal analysis: A case study of simultaneous electromagnetic disturbances

In multi-causal analysis, the independence of causal influence (ICI) assumed by the noisy-OR (NOR) model can be used to predict the probability of the effect when several causes are present simultaneously, and to identify (when it fails) inter-causal dependence (ICD) between them. The latter is possible only if the probability of observing the multi-causal effect is available for comparison with a corresponding NOR estimate. Using electromagnetic interference in an integrated circuit as a case study, the data corresponding to the probabilities of observing failures (effect) due to the injection of individual (single cause) and simultaneous electromagnetic disturbances having different frequencies (multiple causes) were collected. This data is initially used to evaluate the NOR model and its existing derivatives, which have been proposed to reduce the error in predictions for higher-order multi-causal interactions that make use of the available information on lower-order interactions. Then, to address the identified limitations of the NOR and its existing derivatives, a new deterministic model called Super-NOR is proposed, which is based on correction factors estimated from the available ICD information.