Kenichi Yamazaki

Central Research Institute of Electric Power Industry | CRIEPI · Electric Facility Technology Division

Worker exposure to high-intensity magnetic fields encountered during bare-handed live-line working on a conductor of an overhead transmission line is a major safety concern. In this article, internal ( in situ ) electric fields in a live-line worker induced by power frequency magnetic fields were numerically calculated considering realistic exposu...

In this study, the internal (in situ) electric field induced in human tissues by ELF and intermediate frequency uniform magnetic fields has been determined using the scalar potential finite difference (SPFD) method. These calculations were conducted on adult Japanese numerical models and the calculation results were compared with the DRL (dosimetri...

We assessed human exposure to radiofrequency (RF) electromagnetic fields used for a wireless communication system installed on a smart meter for communication in the 920 MHz band. In an exposure guideline, the specific absorption rate (SAR) is used as a measure of the thermal effects of human exposure to electromagnetic fields. Although the low‐pow...

We assessed human exposure to radiofrequency (RF) electromagnetic fields used for a wireless communication system installed on a smart meter for communication in the 920 MHz band. In an exposure guideline, the specific absorption rate (SAR) is used as a measure of the thermal effects of human exposure to electromagnetic fields. Although the low-pow...

Protection of human from exposures to electric and magnetic fields has received public concerns for decades. Methods to assess physical quantities related to the exposure, such as artificially generated electric and magnetic fields, electric fields inside human body caused by the exposures, and contact currents, have been investigated and establish...

The technical committee on electromagnetic compatibility (EMC) was established under the Fundamentals and Materials Society (FMS), the Institute of Electrical Engineers in Japan (IEEJ) in 1999. Since then, researches and investigations related to this field have been conducted actively in the committee. In this report, trends and current activities...

Protection of human from exposures to electric and magnetic fields have received public concerns for decades. Methods to assess physical quantities related to the exposure, such as artificially generated electric and magnetic fields, electric fields inside human body caused by the exposures, and contact currents, have been investigated and establis...

The newly released IEEE Std C95.1™-2019 defines exposure criteria and associated limits for the protection of persons against established adverse health effects from exposures to electric, magnetic, and electromagnetic fields, in the frequency range 0 Hz to 300 GHz. The exposure limits apply to persons permitted in restricted environments and to th...

Regarding evaluation of human safety for exposure to ELF (extremely low frequency) electric field, numerical electromagnetic calculation on anatomical human model is carried out to obtain an induced inner electric field. In previous studies, calculation results using QS-FDTD (quasi static finite difference time domain) or SPFD (scalar potential fin...

In this study, the internal (in-situ) electric field induced in human tissues by ELF and intermediate frequency uniform magnetic fields has been determined using the scalar potential finite difference (SPFD) method. These calculations were conducted on adult Japanese numerical models and the calculation results were compared with the basic restrict...

The technical committee on electromagnetic compatibility (EMC) was established under the Fundamentals and Materials Society (FMS), the Institute of Electrical Engineers in Japan (IEEJ) in 1999. Since then, researches and investigations related to this field have been conducted actively in the committee. In this report, historical trends and current...

We developed a two-step process method combining the fast-multipole surface charge method and the SPFD (scalar potential finite difference) method to evaluate electric field induced in a human body which is exposed to extremely low frequency (ELF) electric field. Since any electric quantity outside the body does not need to be taken into account in...

IEEE C95.1 (radio frequency) and C95.6 (low frequency) standards for human protection from electromagnetic fields are currently under revision. In the next revision, they will be combined into one standard covering the frequency range from 0 Hz to 300 GHz. Although the C95.1 standard considers anatomical human models for deriving the relationship b...

The technical committee on electromagnetic compatibility (EMC) was established under the Fundamentals and Materials Society (FMS), the Institute of Electrical Engineers in Japan (IEEJ) in 1999. Since then, researches and investigations related to this field have been conducted actively in the committee. In this report, historical trends and current...

In 2010, the international commission on non-ionizing radiation protection (ICNIRP) guidelines provided the reference levels of contact currents in the frequency range from 1 Hz to 10 MHz. These restrictions are based on the threshold levels of electric shocks of human volunteers in response to sinusoidal contact current stimuli except transient cu...

The “intermediate frequency” electromagnetic fields in the context of protecting human exposure have received public concerns in recent years. This is mainly due to the growing emergence of technology or products using those fields, such as induction heating (IH) cookers and wireless power transfer (WPT) systems. This paper reviews the trend of stu...

Magnetic field induction from an overhead power line to a nearby parallel multipoint grounded conductor is discussed. By applying the Thevenin's equivalent circuit to a terminal (contact points) in a multipoint grounded conductor, simple useful formulae to evaluate the induced voltage on the conductor were derived. It revealed that distinctly small...

In electric power systems, microwave relay stations are employed to exchange information using electromagnetic radio waves to control the systems. Some microwave relay stations are built on tops of mountains, which causes a high incidence of lightning strikes to microwave towers, and the lightning strikes may result in disturbances of microwave rad...

Microwave relay stations are key components in controlling power grids and maintaining their stability, but lightning strikes to the stations may cause faults, malfunctions, or even physical damage to microwave radio equipment. To protect equipment from lightning, it is necessary to predict surge phenomena in a microwave relay station, and design e...

The "intermediate frequency" electromagnetic fields in the context of protecting human exposure have received public concerns in recent years. This is mainly due to the growing emergence of technology or products using those fields, such as induction heating (IH) cookers and wireless power transfer (WPT) systems. This paper reviews the trend of stu...

The operating voltages of low-voltage control circuits in power stations and substations have become lower with the installation of digital control equipment. This significantly increases the risk of faults and malfunctions of the circuits resulting from overvoltages in the control circuits due to lightning and switching surges. Therefore, the char...

The present study provides an intercomparison of the induced quantities in a human model for uniform magnetic field exposures at extremely low frequency. A total of six research groups have cooperated in this joint intercomparison study. The computational conditions and numeric human phantom including the conductivity of tissue were set identically...

The operating voltages of low-voltage control circuits in power plants and substations have become lower owing to the installation of digital-control equipment. This significantly increases the risk of faults and malfunctions of such circuits due to abnormal voltages in the control circuits induced by lightning and switching surges. Therefore, the...

Regarding compliance testing with existing guidelines on human exposure to ELF (extremely low frequency) magnetic fields, the nonuniformity of the fields has been one of the major concerns since guideline-level exposures are generally encountered in the direct vicinity of magnetic field sources such as electric power facilities and electric applian...

Concerns have been raised regarding the relationship between electromagnetic fields and human health. Compared to the research on extremely low frequency (ELF) and radio frequency (RF) electromagnetic fields, very few studies have addressed the biological effects of the electromagnetic field with intermediate frequency (IF) from 300 Hz to 10 MHz. T...

How high an electric field or current is induced inside a human body when exposed to an electromagnetic field has recently attracted much attention. The background for this is twofold; concern about the possible health effects of electromagnetic fields (usually called ‘EMF issues’), and their positive application to medical treatment or new researc...

For a variety of reasons, induced current has long been considered to be the most important measure of dose when dealing with biological effects of applied or induced currents and fields. Electrostimulation has a long history in biology, dating back to the work of Galvani and Volta in the early 19th century. Furthermore, the basic mathematical tool...

Regarding recent concerns on the health effects of ELF (extremely low frequency) magnetic fields, compliance testing in accordance with guidelines in highly non-uniform magnetic field has been a critical issue. In these cases, when the measured maximum magnetic fields on the surface of the human body exceed the reference level, the basic restrictio...

An RF survey meter is often used to evaluate the safety of human exposure to RF electromagnetic fields. However, it has been noted that erroneous meter indications occur when the meters are used in strong, extremely low-frequency (ELF) electric fields, such as those found near electric power transmission and distribution facilities. In this paper,...

The conditions under which corona first occurs for any set of electrodes are an important design consideration since corona can limit the performance of any given configuration of electrical conductors. Here, the 60 Hz ac corona onset voltage for a stranded wire in air is calculated. The criterion involves the characteristics, i.e. composition and...

A previously proposed simple method to characterize magnetic fields near electric appliances was extended to intermediate frequencies of up to 100 kHz. The method consists of identification of the magnetic dipole moment that is equivalent to a magnetic field source of an electric appliance and simple estimation of the magnetic field distribution ar...

A simple method of quantifying the ELF (extremely low frequency) magnetic field distribution around electric appliances, which takes the harmonics into account, is newly proposed. The proposed method involves: (1) a simple estimation of the position of an equivalent magnetic dipole moment inside an appliance, using two magnetic field meters; (2) id...

Regarding the possible biological effects caused by exposure to ELF (extremely low frequency) magnetic fields, magnetically induced current inside the human boldy has been a focus of research. To clarify the induced current characteristics inside the human body, we develop estimation tools. One was a numerical calculation code and the other was a h...

We have studied experimentally the shielding method of ELF magnetic field applied to the source of line conductors. For the single-phase line current, it appears to be difficult to achieve effective shielding. On the other hand, for the balanced three-phase conductors, including triangle and twisted configuration, a certain reduction of generated m...

An exposure facility for wide application to cell exposure to an ELF (extremely low frequency) magnetic field was developed. It is suitable for conducting experiments under a high-intensity, variable-frequency magnetic field, on the biological effects of the ELF magnetic field in an in vitro study. The exposure system consists of Merritt's 4-square...

Estimation of induced current inside a human body exposed to ELF (extremely low frequency) magnetic field are still remaining as an important issue. There are many computational studies reporting the relationship between outer magnetic filed and induced current inside the human body. In addition, there are some limit values regarding human exposure...

Summary form only given as follows. Magnetic field mitigation for overhead power lines using a passive loop conductor was studied. The aim of this study is to clarify the requirements for effective mitigation not in a specific region such as at the edge of the ROW (right of way) but everywhere around the conductors. For this purpose, the concept of...

Regarding the possibility of biological effects caused by exposure to ELF (extremely low frequency) magnetic fields, magnetically induced current inside the human body has been a focus of research. To clarify the induced current characteristics inside the human body, we developed estimation tools. One was a numerical calculation code and the other...

A feasibility study for development of a non-contacting voltage presence detector was performed. This detector is intended to be used for maintenance of the overhead transmission lines. A detection method by measurement of electric field on the surface of the tower post was proposed and investigated by means of electric field measurements at the tr...

This study was conducted to determine if exposure to 50 Hz magnetic field (MF) affects intracellular calcium ([Ca2+]i). We employed flow cytometry for real-time detection of possible changes in [Ca2+]i in a large number of cells. A solenoid coil for vertical MF exposure and a multiple-loop square-coil for horizontal MF were utilized. In the laborat...

Since concerns have been expressed regarding the environmental effects of ELF (Extremely Low Frequency) magnetic fields, it is important to establish a method for mitigation of the magnetic fields around electric power facilities. We previously reported a method to reduce the magnetic field generated from underground cables using cylindrical shield...

In order to understand possible effects of magnetic fields exposure on biological system, it is important to carry out the experiments under well defined experimental conditions. Circularly polarized, elliptically polarized at various ratios of major versus minor axes, as well as linearly polarized fields can be found under AC three-phase transmiss...

We have studied experimentally the shielding method of ELF magnetic field applied to the source of line conductors. For the single-phase line current, it appears to be difficult to achieve the effective shielding. On the other hand, for the balanced 3-phase conductors, including triangle and twisted configuration, a certain reduction of generated m...

In the study of clarifying the biological effects caused by ELF (Extremely Low Frequency) magnetic fields, we have concentrated on induced currents because the induced current is considered an inner index of outer magnetic fields. By surveying the results of animal experiments, we consider that it is significant to clarify the difference of induced...

In order to assess the biological effects of exposure of small animals to ELF magnetic fields, the characteristics of induced currents and deposited power density in a rat's head model were analyzed. The characteristics of induced current distribution in the spheroidal rat's brain model and the induced current difference with different field polari...

We have developed the Valvo-Pump, an axial flow blood pump, which is implanted at the natural heart valve position. This device has several advantages; it fits well anatomically, its blood-contacting surface is small because the left or right ventricular cavity is used as the blood storage reservoir, and it is implanted as easily as an artificial h...

The valvo-pump, an axial nonpulsatile blood pump implanted at the heart valve position, has been developed. The valvo-pump consists of an impeller and a motor, which are encased in a housing. An impeller with 5 vanes (22.0 mm in diameter) is used. The impeller is connected to a samarium-cobalt-rare earth magnet direct current (DC) brushless motor m...

The valvo-pump, an axial, nonpulsatile blood pump implanted at the heart valve position while preserving diseased heart muscle, has several advantages over an artificial heart replacement, including 1) a good anatomic fit to the natural heart, 2) less blood contacting surface, and 3) ease of implantation. The housing for the pump is a tube, 37 mm i...

Journal of Human Muscle Performance (discontinued journal) Vol. 1, No. 1, pp. 1-15 (1991)