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(Database last updated on Mar 27, 2024)
| ID Number | 1911 | |
| Study Type | Engineering & Physics | |
| Model | Emissions/Exposure Measurements (ELF catch all) | |
| Details | Emissions Measurements (ELF catch all) AUTHORS' ABSTACT: Korpinen et al. 2013 (IEEE #5442): The aim of the study was to analyze all current values from measured periods while performing tasks on 400 kV power lines. Our aim was also to study the average current densities and average total contact currents caused by electric fields in 400 kV power line tasks. Two workers simulated the following tasks: (A) climbing up a portal tower, (B) climbing up a portal transposing tower, (C) working on the cross-arm of a portal tower, (D) climbing up a portal tube tower, (E) climbing up a Tannenbaum tower on the side of the energized circuit with the other circuit unenergized, (F) climbing up a Tannenbaum tower with both circuits energized, and (G) climbing up a Donau tower. The highest average current density in the neck was 2.5 mA/m2 (calculated internal electric field 31.563.0 mV/m), and the highest average of the contact currents was 240.0 mA. All measured values at 400 kV towers were lower than the limit value of 10 mA/m2 in the first version of Directive 2004/40/EC and the basic restrictions (0.1 and 0.8 V/m) of the International Commission on Non-ionizing Radiation Protection. AUTHORS' ABSTRACT: Tarao, Korpinen et al. 2013 (IEEE #5443): An ungrounded human, such as a substation worker, receives contact currents when touching a grounded object in electric fields. In this article, contact currents and internal electric fields induced in the human when exposed to non-uniform electric fields at 50 Hz are numerically calculated. This is done using a realistic human model standing at a distance of 0.10.5 m from the grounded conductive object. We found that the relationship between the external electric field strength and the contact current obtained by calculation is in good agreement with previous measurements. Calculated results show that the contact currents largely depend on the distance, and that the induced electric fields in the tissues are proportional to the contact current regardless of the non-uniformity of the external electric field. Therefore, it is concluded that the contact current, rather than the spatial average of the external electric field, is more suitable for evaluating electric field dosimetry of tissues. The maximum induced electric field appears in the spinal cord in the central nervous system tissues, with the induced electric field in the spinal cord approaching the basic restriction (100 mV/m) of the new 2010 International Commission on Non-Ionizing Radiation Protection guidelines for occupational exposure, if the contact current is 0.5 mA. AUTHORS' ABSTRACT: Korpinen, Kuisti and Elovaara 2014 (IEEE 5795): The aim of this study was to analyze all values of electric current from measured periods while performing tasks on 110 and 220 kV power lines. Additionally, the objective was to study the average current densities and average total contact currents caused by electric fields in 110 and 220 kV power line tasks. One worker simulated the following tasks: (A) tested insulation voltage at a 110 kV portal tower, (B) checked the wooden towers for rot at a 110 kV portal tower, (C) tested insulation voltage at a 220 kV portal tower, and (D) checked the wooden towers for rot at a 220 kV portal tower. The highest average current density in the neck was 2.0 mA/m(2) (calculated internal electric field was 19.0-38.0 mV/m), and the highest average contact current was 234 µA. All measured values at 110 and 220 kV towers were lower than the basic restrictions (0.1 and 0.8 V/m) of the International Commission on Non-ionizing Radiation Protection. AUTHORS' ABSTRACT: Korpinen et al. 2014 (IEEE #5796): The object of the study was to investigate extremely low frequency (ELF) electric field exposure measurement methods under power lines. The authors compared two different methods under power lines: in Method A, the sensor was placed on a tripod; and Method B required the measurer to hold the meter horizontally so that the distance from him/her was at least 1.5 m. The study includes 20 measurements in three places under 400 kV power lines. The authors used two commercial three-axis meters, EFA-3 and EFA-300. In statistical analyses, they did not find significant differences between Methods A and B. However, in the future, it is important to take into account that measurement methods can, in some cases, influence ELF electric field measurement results, and it is important to report the methods used so that it is possible to repeat the measurements. AUTHORS' ABSTRACT: Li and Wu 2015 (IEEE #5923): Infant exposure to 50 Hz magnetic fields from power lines was numerically analyzed in this study. Dosimetric variability due to posture and skin-to-skin contact was evaluated using human anatomical models including a recently developed model of a 12-months-old infant. As proposed by the International Commission on Non-Ionizing Radiation Protection, the induced E-field strength (99th percentile value, E99) for the central nerve systems (E99_CNS) and peripheral nerve system (E99_PNS), were used as metrics. Results showed that the single (free of contact with others) infant model has lower E99 (E99_CNS and E99_PNS inclusive) compared with single adult and child models when exposed to the same power-frequency magnetic field. Also, studied postures of sitting, standing, or arm-up, would not change E99_PNS. However, skin-to-skin contact with other models could significantly raise induced E-field strength in the infant (e.g., contact on 0.93% of the infants total surface increased E99_PNS by 213%). Simulations with canonical models were conducted to assess different factors contributing to the E99 enhancement. Results indicated the importance of thoroughly investigating the conservativeness of current safety guidelines in the case of skin-to-skin contact, especially with infants. AUTHORS' ABSTRACT; Tarao et al. 2016 IIEEE #6468): Most results regarding induced current in the human body related to electric field dosimetry have been calculated under uniform field conditions. We have found in previous work that a contact current is a more suitable way to evaluate induced electric fields, even in the case of exposure to non-uniform fields. If the relationship between induced currents and external non-uniform fields can be understood, induced electric fields in nervous system tissues may be able to be estimated from measurements of ambient non-uniform fields. In the present paper, we numerically calculated the induced electric fields and currents in a human model by considering non-uniform fields based on distortion by a cubic conductor under an unperturbed electric field of 1 kV m1 at 60 Hz. We investigated the relationship between a non-uniform external electric field with no human present an d the induced current through the neck, and the relationship between the current through the neck and the induced electric fields in nervous system tissues such as the brain, heart, and spinal cord. The results showed that the current through the neck can be formulated by means of an external electric field at the central position of the human head, and the distance between the conductor and the human model. As expected, there is a strong correlation between the current through the neck and the induced electric fields in the nervous system tissues. The combination of these relationships indicates that induced electric fields in these tissues can be estimated solely by measurements of the external field at a point and the distance from the conductor. |
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| Findings | ||
| Status | Completed With Publication | |
| Principal Investigator | ||
| Funding Agency | ????? | |
| Country | FINLAND | |
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