scholarly journals Distribution of Magnetic Field in 400 kV Double-Circuit Transmission Lines

2020 ◽  
Vol 10 (9) ◽  
pp. 3266 ◽  
Author(s):  
Ramūnas Deltuva ◽  
Robertas Lukočius
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Transmission Line ◽  
Magnetic Field Strength ◽  
Transmission Lines ◽  
Power Transmission ◽  
Power Transmission Line ◽  
Overhead Transmission Line ◽  
The City ◽  
The Magnetic Field

A high-voltage AC double-circuit 400 kV overhead power transmission line runs from the city of Elk (Poland) to the city of Alytus (Lithuania). This international 400 kV power transmission line is potentially one of the strongest magnetic field-generating sources in the area. This 400 kV voltage double-circuit overhead transmission line and its surroundings were analyzed using the mathematical analytical methods of superposition and reflections. This research paper includes the calculation of the numerical values of the magnetic field and its distribution. The research showed that the values of the magnetic field strength near the international 400 kV power transmission line exceed the threshold values permitted by relevant standards. This overhead power line is connected to the general (50 Hz) power system and generates a highly intense magnetic field. It is suggested that experimental trials should be undertaken in order to determine the maximum values of the magnetic field strength. For the purpose of mitigating these values, it is suggested that the height of the support bars should be increased or that any individual and commercial activities near the object under investigation should be restricted.

scholarly journals Electric and magnetic field of different transpositions of overhead power line

2017 ◽  
Vol 66 (3) ◽  
pp. 595-605 ◽  
Author(s):  
Ramūnas Deltuva ◽  
Robertas Lukočius
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Electric Field ◽  
Transmission Line ◽  
Electric Field Strength ◽  
Power Transmission ◽  
Power Transmission Line ◽  
Limit Values ◽  
Electric Power Supply ◽  
Overhead Power Transmission Line

AbstractIn Lithuanian and Polish electric power supply systems, the power transmission lines of 400 kV voltage represent one of the most potential sources of electric and magnetic fields generation. The 400 kV double-circuit overhead power transmission line and its surrounding environment were herby described and simulated through Finite Element Method usingCOMSOL Multiphysicsoftware package. This study includes magnetic and electric field calculations. The study shows that the values of magnetic field strength and electric field strength present in the vicinity of a 400 kV overhead power transmission line tend to exceed limit values established in the Normative. Measurements are suggested to be taken for the purpose of finding maximum values of magnetic and electric field strength. To reduce these values, it is recommended to increase the height of supports, and restrict human personal and economic activities.

Analysis on the Electromagnetic Environmental Factors of 500kV Double Circuit Transmission Line

2012 ◽  
Vol 599 ◽  
pp. 884-887
Author(s):  
Jian Zhao Qi ◽  
Jing Yi Li
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Transmission Line ◽  
Magnetic Field Strength ◽  
Transmission Lines ◽  
Parameters Optimization ◽  
Electromagnetic Environment ◽  
Minimal Impact ◽  
Phase Sequence ◽  
Frequency Magnetic Field

This paper calculates frequency magnetic field strength by the Ampere's law, and analyzes the main factors affecting the electromagnetic environment of the 500kV Double Circuit Transmission Lines. In the same electromagnetic transmission line calculation parameters, optimization of phase sequence can effectively reduce the frequency magnetic field strength; with the increase of the distance, the line frequency magnetic field strength significantly reduces away from the center line within 25m. Finally, the paper obtains the phase sequence arrangement with minimal impact on the electromagnetic environment and the minimum ground clearance meeting the environmental requirements.

scholarly journals Methodology to calculate the density of the magnetic field generated in overhead transmission lines in HVDC applying a two-dimensional analysis of parallel poles above ground level

2020 ◽  
pp. 1-11
Author(s):  
Jorge Luis AGUILAR-MARIN ◽  
Luis CISNEROS-VILLALOBOS ◽  
Jorge Gabriel PADILLA-CANTERO ◽  
Julio Cesar VERGARA-VÁZQUEZ
Keyword(s):  
Magnetic Field ◽  
Transmission Line ◽  
Transmission Lines ◽  
Ground Level ◽  
Design Parameters ◽  
Hvdc Transmission ◽  
Overhead Transmission Line ◽  
The Impact ◽  
The Magnetic Field

The growth in the demand for electricity has led to the development and application of technologies that make its means of transport more efficient. Thus, one of these options is the implementation of transmission lines in HVDC. One of important design parameters of these lines is to know their magnetic field distribution, when it is required to calculate it, there is no methodology that can be applied to HVDC transmission lines. The following article presents a methodology that allows obtaining the density of the magnetic field on the corridor of an overhead transmission line. A case study of a 500 kV bipolar line in HVDC is presented, the results obtained are compared using the commercial software Field and corona Effects (FACE), the results obtained are consistent with those obtained from the presented methodology. An analysis of the impact of the transmission line configuration on the magnetic field density is developed, defining the most efficient configuration.

scholarly journals Enhanced analytical model of power transmission line icing

2018 ◽  
Vol 11 (3) ◽  
pp. 222-226
Author(s):  
M. V. Timofeeva
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Transmission Line ◽  
Analytical Model ◽  
Transmission Lines ◽  
Wind Direction ◽  
Power Transmission ◽  
Weather Conditions ◽  
Power Transmission Line ◽  
Power Transmission Lines

Accidents in power transmission lines under icing conditions, in particular, those of cables, cause a great economic damage in Russia. Because of the lack of the possibility to forecast and evaluate reliably the consequences of weather conditions contributing to icing of transmisison line cables, power grid services often have to go to the place of a potential accident relying on guesswork. This leads to considerable losses of time and material resources, while the average recovery time of a damaged high voltage power transmission line is 5–10 days.For the effective prediction and timely prevention of negative consequences of icing of on power line cables, an analytical model that describes the growth of ice on the surface of the electrical cable has been developed. The model is based on a widely applicable analytical model of [1], supplemented with dependence of the growth of ice sleeve on the angle between the wind direction and the cable, and on the electric field strength of the cable.The results obtained using the new analytical model and the [1], model have been compared and show that as the angle between the wind direction and the cable decreases, the intensity of the ice growth decreases significantly. At the same time, the strength of the electric field of the cable affects negligibly the trajectory of water droplets.A conclusion is drawn about insignificance of electrical field strength of the electric cable as a factor of growth of ice deposits. It is stated that the ice thickness value obtained using the developed model can be increased under specific weather conditions and design parameters of transmission lines. The obtained model can be improved by using other physical effects that affect icing of electric cables. Further, the model can be introduced in operation of energy companies to monitor the condition of power transmission lines and to carry out anti-icing activities.

On the Configuration of the Magnetic Field of β CrB

1976 ◽  
Vol 32 ◽  
pp. 613-622
Author(s):  
I.A. Aslanov ◽  
Yu.S. Rustamov
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Radial Velocity ◽  
Magnetic Field Strength ◽  
Complex Shape ◽  
Rotation Period ◽  
Field Variation ◽  
Magnetic Field Variation ◽  
Secular Variations ◽  
The Magnetic Field

SummaryMeasurements of the radial velocities and magnetic field strength of β CrB were carried out. It is shown that there is a variability with the rotation period different for various elements. The curve of the magnetic field variation measured from lines of 5 different elements: FeI, CrI, CrII, TiII, ScII and CaI has a complex shape specific for each element. This may be due to the presence of magnetic spots on the stellar surface. A comparison with the radial velocity curves suggests the presence of a least 4 spots of Ti and Cr coinciding with magnetic spots. A change of the magnetic field with optical depth is shown. The curve of the Heffvariation with the rotation period is given. A possibility of secular variations of the magnetic field is shown.

scholarly journals Time-Multiplexed Self-Powered Wireless Current Sensor for Power Transmission Lines

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1561
Author(s):  
Hao Chen ◽  
Zhongnan Qian ◽  
Chengyin Liu ◽  
Jiande Wu ◽  
Wuhua Li ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Transmission Line ◽  
Transmission Lines ◽  
Power Transmission ◽  
Current Measurement ◽  
Current Sensor ◽  
Power Transmission Line ◽  
Power Transmission Lines ◽  
Current Sensing ◽  
Self Powered

Current measurement is a key part of the monitoring system for power transmission lines. Compared with the conventional current sensor, the distributed, self-powered and contactless current sensor has great advantages of safety and reliability. By integrating the current sensing function and the energy harvesting function of current transformer (CT), a time-multiplexed self-powered wireless sensor that can measure the power transmission line current is presented in this paper. Two operating modes of CT, including current sensing mode and energy harvesting mode, are analyzed in detail. Through the design of mode-switching circuit, harvesting circuit and measurement circuit are isolated using only one CT secondary coil, which eliminates the interference between energy harvesting and current measurement. Thus, the accurate measurement in the current sensing mode and the maximum energy collection in the energy harvesting mode are both realized, all of which simplify the online power transmission line monitoring. The designed time-multiplexed working mode allows the sensor to work at a lower transmission line current, at the expense of a lower working frequency. Finally, the proposed sensor is verified by experiments.

scholarly journals The effects of magnetic field strength on the properties of wind generated from hot accretion flow

2018 ◽  
Vol 615 ◽  
pp. A35 ◽  
Author(s):  
De-Fu Bu ◽  
Amin Mosallanezhad
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Pressure Gradient ◽  
Magnetic Field Strength ◽  
Magnetic Pressure ◽  
Gas Pressure ◽  
Accretion Flow ◽  
Accretion Flows ◽  
Black Hole Accretion ◽  
The Magnetic Field

Context. Observations indicate that wind can be generated in hot accretion flow. Wind generated from weakly magnetized accretion flow has been studied. However, the properties of wind generated from strongly magnetized hot accretion flow have not been studied. Aims. In this paper, we study the properties of wind generated from both weakly and strongly magnetized accretion flow. We focus on how the magnetic field strength affects the wind properties. Methods. We solve steady-state two-dimensional magnetohydrodynamic equations of black hole accretion in the presence of a largescale magnetic field. We assume self-similarity in radial direction. The magnetic field is assumed to be evenly symmetric with the equatorial plane. Results. We find that wind exists in both weakly and strongly magnetized accretion flows. When the magnetic field is weak (magnetic pressure is more than two orders of magnitude smaller than gas pressure), wind is driven by gas pressure gradient and centrifugal forces. When the magnetic field is strong (magnetic pressure is slightly smaller than gas pressure), wind is driven by gas pressure gradient and magnetic pressure gradient forces. The power of wind in the strongly magnetized case is just slightly larger than that in the weakly magnetized case. The power of wind lies in a range PW ~ 10−4–10−3 Ṁinc2, with Ṁin and c being mass inflow rate and speed of light, respectively. The possible role of wind in active galactic nuclei feedback is briefly discussed.

COMPARISON OF CARDIAC MAGNETIC FIELD DISTRIBUTIONS DURING DEPOLARIZATION AND REPOLARIZATION

2003 ◽  
Vol 13 (12) ◽  
pp. 3783-3789 ◽  
Author(s):  
F. E. SMITH ◽  
P. LANGLEY ◽  
L. TRAHMS ◽  
U. STEINHOFF ◽  
J. P. BOURKE ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Field Distribution ◽  
Normal Subjects ◽  
The Body ◽  
Magnetic Field Distribution ◽  
T Wave ◽  
High Magnetic Field Strength ◽  
The Magnetic Field

Multichannel magnetocardiography measures the magnetic field distribution of the human heart noninvasively from many sites over the body surface. Multichannel magnetocardiogram (MCG) analysis enables regional temporal differences in the distribution of cardiac magnetic field strength during depolarization and repolarization to be identified, allowing estimation of the global and local inhomogeneity of the cardiac activation process. The aim of this study was to compare the spatial distribution of cardiac magnetic field strength during ventricular depolarization and repolarization in both normal subjects and patients with cardiac abnormalities, obtaining amplitude measurements by magnetocardiography. MCGs were recorded at 49 sites over the heart from three normal subjects and two patients with inverted T-wave conditions. The magnetic field intensity during depolarization and repolarization was measured automatically for each channel and displayed spatially as contour maps. A Pearson correlation was used to determine the spatial relationship between the variables. For normal subjects, magnetic field strength maps during depolarization (R-wave) showed two asymmetric regions of magnetic field strength with a high positive value in the lower half of the chest and a high negative value above this. The regions of high R-wave amplitude corresponded spatially to concentrated asymmetric regions of high magnetic field strength during repolarization (T-wave). Pearson-r correlation coefficients of 0.7 (p<0.01), 0.8 (p<0.01) and 0.9 (p<0.01) were obtained from this analysis for the three normal subjects. A negative correlation coefficient of -0.7 (p<0.01) was obtained for one of the subjects with inverted T-wave abnormalities, suggesting similar but inverted magnetic field and current distributions to normal subjects. Even with the high correlation values in these four subjects, the MCG was able to identify differences in the distribution of magnetic field strength, with a shift in the T-wave relative to the R-wave. The measurement of cardiac magnetic field distribution during depolarization and repolarization of normal subjects and patients with clinical abnormalities should enable the improvement of theoretical models for the explanation of the cardiac depolarization and repolarization processes.

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