Fundamental study on measurement of ELF electric field at biological body surfaces

Our previous study examined the neural effects of extremely low frequency electric field (ELF-EF) using electroencephalogram (EEG) and heart rate variability (HRV) measurement and revealed that the theta power of EEG increases during 1-min EF treatment (30 kV and 50 Hz). In the present study, the effects of a longer treatment duration were assessed. EF was applied between two electrodes, one above the head and the other under the feet, for 20 min to 10 healthy men sitting on a chair. Occipital EEG and HRV were measured in the eyes-open condition. Power spectrum analysis showed that during the EF treatment, the power of alpha and theta rhythms as well as the low frequency component of HRV increased, and the heart rate decreased. These effects did not persist after the end of EF treatment. It is suggested that ELF-EF treatment alters not only the brain activity but also the autonomic activity reflected in HRV.

“…Generation of ELF‐EF effects through the movement of skin hair have been previously studied [37]. ELF‐EF oscillates the hair and stimulates the nerve in the skin.…”

Section: Discussionmentioning

confidence: 99%

Alterations in Heart Rate Variability and Electroencephalogram during20‐MinuteExtremely Low Frequency Electric Field Treatment in Healthy Men during theEyes‐OpenCondition

Shinba

Nedachi

Harakawa

2022

“…4). This dosimetry system was originally developed by our collaborators [17,18] and modified for our study.…”

Section: Methodsmentioning

confidence: 99%

Extremely Low‐Frequency Electric Field Exposure Increases Theta Power of EEG in both Eyes‐Open and Eyes‐Closed Resting Conditions in Healthy Male Subjects

Shinba

Nedachi

Harakawa

2021

The effects of extremely low-frequency (ELF) electric field (EF) exposure on brain activity remain poorly understood. This study sought to examine the acute effects of EF exposure on brain activity by analyzing electroencephalogram (EEG) basic rhythms. The heart rate variability (HRV) was also measured to evaluate autonomic activity. Using a system that enables measurement under EF exposure, occipital EEG and electrocardiogram signals were recorded in nine healthy male subjects during daytime in eyes-open and eyes-closed conditions, with or without EF exposure (applied voltage: 30 kV, 50 Hz for 1 min). The EEG power and frequency-domain HRV indices were obtained by power spectrum analysis of EEG and the RR interval trend, respectively. Resulting data revealed that the theta power of EEG was significantly greater during EF exposure in eyes-open and eyes-closed conditions. Other EEG rhythms and HRV indices were not affected by EF exposure. These findings suggest that exposure to 50-Hz EF for 1 min altered brain activity by increasing the theta power.

“…By demodulating the current signal, the corresponding electric field strength can be obtained. The device needs calibration before conducting the electric field measurements in the substation. Figure shows the calibration test layout of the measurement device in a large, uniform electric field.…”

Section: Electric Field Measurements At Ground Potentialmentioning

confidence: 99%

1000‐kV UHV substation live working and safety recommendations

Fang

Rehman

Xiao³

et al. 2018

This work focuses on the measurement and analysis of the electric field for live working in a 1000‐kV substation. Also, it compares the electric field and the shielding efficiency requirement of a 1000‐kV substation with 1000‐kV transmission lines. The electric field at the ground potential of the substation was measured using a microelectromechanical system (MEMS)‐based device. However, for safety reasons and to acquire rigorous data, finite element method (FEM) was applied to calculate the electric field at equipotential. Two cases of entry into equipotential were considered: one in which the worker moves along tension insulators to live conductors, and another where the worker is lifted to an energized bus bar on an insulated elevating platform. Our results indicate that the electric field values on the worker in the 1000‐kV substation and transmission lines are about the same at ground potential, while at equipotential, the substation's maximum electric field is 25.2% higher outside the conductive clothing and 47.4% higher outside the metallic mask as compared to the 1000‐kV transmission lines. Based on these results, for live working in a 1000‐kV substation, we recommend the use of conductive clothing with 60‐dB shielding efficiency, which is similar to that used in live working on a 1000‐kV transmission line, but the metallic mask should have 25‐dB shielding efficiency, which is 5 dB higher than that used for the transmission line. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.