| In order to solve the contradiction between the reverse distribution of energy resources and load centers in our country,China has been vigorously developing cross-regional ultra high voltage(UHV)transmission interconnection projects in recent years,which plays an important role in promoting coordinated development among regions and realizing the optimal allocation of energy resources nationwide.At the same time,the electromagnetic exposure of UHV alternating current(AC)transmission lines is more and more drawing people's attention and worry.In the light of the lack of literature to study the interaction between the electromagnetic field and the human body,this thesis used electromagnetic dosimetry method to calculate both the power frequency magnetic field effect and power frequency electric field effect of the human body under typical single-circuit and double-circuit towers with UHV AC transmission lines.The safety assessments were carried out according to the electromagnetic exposure protection guidelines specified by the International Commission on Non-Ionizing Radiation Protection(ICNIRP).For the purpose of carrying out safety assessments of the electromagnetic exposure under single-circuit and double-circuit towers with 1000 kV UHV AC transmission lines,the thesis firstly established a three-dimensional standing adult human model with a total height of 1.75 meters.Secondly,relative permittivities and conductivities of the major human tissues were calculated with the fourth-order Cole-Cole model.The single-circuit towers adopted the typical cup tower and cat-head tower in the Jindongnan-Nanyang-Jingmen 1000 kV UHV AC demonstration project,while the double-circuit towers adopted the typical drum-shaped tower and umbrella-shaped tower in the Huainan-Shanghai 1000 kV UHV AC transmission project.Then,eight three-dimensional electromagnetic exposure safety assessment mathematical models were established in the finite element method software to calculate the power frequency magnetic field effect and power frequency electric field effect of the human body under the single-circuit cup tower and cat-head tower transmission lines as well as the double-circuit drum-shaped tower and umbrella-shaped tower transmission lines with belt sag.Finally,the magnitude and distribution of magnetic induction intensity,induced electric field intensity and induced current density in human scalp,skull,brain tissue and trunk for different towers were calculated and safety assessments were carried out according to the ICNIRP electromagnetic exposure protection guidelines.The results showed that the power frequency magnetic field exposure of the single-circuit cup tower and cat-head tower,the double-circuit drum-shaped tower and umbrella-shaped tower transmission lines would not pose a threat to the health of human body.For the power frequency electric field exposure of the single-circuit cup tower transmission lines,general public in the corridor width of the transmission lines needed to take certain protective measures to prevent the excessive induced current density at shank and ankle,while the occupational were safe.For the power frequency electric field exposure of the single-circuit cat-head tower,double-circuit drum-shaped tower and umbrella-shaped tower transmission lines,the general public and the occupational in the corridor width of the transmission lines all needed to take certain protective measures to prevent the excessive induced current density at shank and ankle.From the perspective of electromagnetic exposure dosimetry,the single-circuit cup tower transmission lines were superior to the cat-head tower transmission lines,while the doublecircuit umbrella-shaped tower transmission lines were superior to the drum-shaped tower transmission lines. |
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