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Naito Y.,Shoden Co. | Yanagawa S.,Shoden Co. | Yamamoto K.,Chubu University
2016 33rd International Conference on Lightning Protection, ICLP 2016 | Year: 2016

We applied impulse voltages to an electric vehicle using an impulse voltage generator. The results provide insight into the phenomenological aspects of lightning strikes and characteristics of electric discharge between the wheels and ground. © 2016 IEEE.


Yanagawa S.,Shoden Co. | Natsuno D.,Toyosekkei Co. | Yamamoto K.,Kobe City College of Technology
2011 7th Asia-Pacific International Conference on Lightning, APL2011 | Year: 2011

Accidents caused by natural phenomena such as lightning are serious problems for the diffusions of wind power generations. Those problems affect the safety and reliability of wind turbine generator systems. Most of the breakdowns and malfunctions of the electrical and control systems inside wind turbines are caused by a rise in ground potential due to lightning. To solve those problems, the field tests have been carried out so far. In this paper, new measurements of transient grounding characteristics have been carried out at a wind turbine in the vicinity of the Sea of Japan, and new data of the transient characteristics have been obvious. © 2011 IEEE.


Ishimoto K.,Japan Central Research Institute of Electric Power Industry | Asakawa A.,Japan Central Research Institute of Electric Power Industry | Sato T.,Tohoku Electric Power Co. | Miyama Y.,Shoden Co.
IEEJ Transactions on Power and Energy | Year: 2016

Recently, with the expansion of communication network areas, the number of radio communication stations, built in the neighborhood of customer houses, has increased. If lightning strikes a communication radio tower, part of the lightning current flows into the distribution line and into customer houses. This may cause the failure of distribution lines or customer equipment. To protect distribution lines and customer equipment from lightning faults, it is necessary to analyze the surge phenomena in distribution lines and customer equipment and take appropriate protection measures. In this study, we examined the effect of lightning protection measures for distribution lines and customer equipment against lightning strikes to a communication tower. First, using an actual-scale test distribution line, we measured the lightning current flowing into distribution lines and customer equipment. Secondly, we quantitatively examined the effect of lightning protection measures by lighting surge analysis while changing each parameter. From the experimental and analytical results, we show that the proposed protection measures can reduce the lightning current flowing into distribution lines and customer equipment. © 2016 The Institute of Electrical Engineers of Japan.


Kawabata T.,Shoden Co. | Yanagawa S.,Shoden Co. | Takahashi H.,Chubu University | Yamamoto K.,Chubu University
Electric Power Systems Research | Year: 2015

Recently, the amount of lightning damage has increased with the number of lightning flashes. Therefore, it has become important to understand the features of lightning current damage to electrical and electronic equipment. At wind-turbine sites and tall antenna towers, lightning current waveforms are observed using large-scale Rogowski coils. Data related to the main current measured by the large-scale Rogowski coils and the shunt current that damages the electrical and electronic equipment are useful to establish lightning protection methodologies. In this paper, we present a system developed using a Rogowski coil to measure this shunt current. © 2014 Elsevier B.V. All rights reserved.


Naito Y.,Shoden Co. | Yanagawa S.,Shoden Co. | Yamamoto K.,Chubu University
2014 International Conference on Lightning Protection, ICLP 2014 | Year: 2014

In recent years, the demand for electric vehicles, hybrid vehicles, and other types of environmentally-friendly automobiles has rapidly increased. However, these vehicles require more electronic components than conventional gasoline-fueled vehicles. In particular, electric vehicles are installed with electrical systems in both their control and drive sections, rendering the vehicle vulnerable to lightning surges and other electromagnetic disturbances. Nevertheless, the effects of lightning strokes and associated phenomena on these types of vehicles have yet to be properly studied and identified. In this study, we applied impulse voltages to an electric vehicle, using an impulse voltage generator. The results provide insight into the phenomenological aspects of lightning strikes and characteristics of electric discharge between the wheels and ground. © 2014 IEEE.


Yanagawa S.,Shoden Co. | Yamamoto K.,Chubu University | Naito Y.,Shoden Co. | Takahashi N.,Nissan Motor Co. | Matsui M.,Franklin Japan Co.
Electric Power Systems Research | Year: 2015

Many kinds of electronic equipment have been used in recent automobiles. Eco-friendly automobiles such as electric, fuel-cell and hybrid vehicles have spread rapidly. Those automobiles are usually sensitive to electromagnetic disturbance caused by lightning and so on. When an automobile is struck by lightning, lightning current usually flows into the earth through the vehicle body. The corresponding transient electromagnetic fields appearing inside the vehicle and shunt lightning current through electronics systems are considered sources of malfunctions. From an automobile safety and equipment protection viewpoints, investigations of protective measures are imperative. Before lightning protection methodologies are proposed, existing lightning damages to automobiles must be clarified. The statistical data on automobile lightning damage reports by conducting field surveys and web-based researches had been gathered. In this paper, the result of statistical data has been introduced. Right in the middle of the field surveys of lightning protection for automobiles, the outstanding fire accident of an automobile in Kanto district in Japan occurred. Right after hearing the news, interviews against the fire fighters about their field survey had been conducted; the scene of the accident and burned automobile had also been investigated. In this paper, the results of the interview and investigation have also been discussed. © 2015 Elsevier B.V.


Yamamoto K.,Chubu University | Kawabata T.,Shoden Co. | Yanagawa S.,Shoden Co.
2015 International Symposium on Lightning Protection, XIII SIPDA 2015 | Year: 2015

Various types of signal and control cables are connected to railway signaling systems, and usually those cables are comparatively long. In general, surge protective devices (SPDs) are used as a lightning-protection measure. However, certain types of cables cannot have SPDs due to a fail-safe perspective. In this study, using the Finite Deference Time Domain method and measurements, we confirmed the effects of a method proposed to mitigate overvoltage at two instruments grounded at different places in a railway signal system. The proposed method is that other spare (unoccupied) lines surrounding the control lines in a cable are connected to the ground terminals of instruments existing at both ends of the cable. We have reported the effects of the spare line use on the overvoltage, in comparison with a case of no spare line use. © 2015 IEEE.


Ishii M.,University of Tokyo | Saito M.,University of Tokyo | Sonehara T.,Shoden Co.
IEEJ Transactions on Power and Energy | Year: 2014

Lightning hits to Tokyo Skytree have been under observation by a high-speed camera since August 2012. First data were obtained when negative downward lightning flashes hit the tower on July 08, 2013. This letter reports on observation of a negative single-stroke flash with a positive upward leader initiated from Tokyo Skytree extended about 400m before connection with a downward leader. Simultaneously observed electric field observed by a fast antenna showed much weaker stepped-leader pulses compared to ordinary negative downward flashes hitting ground. © 2014 The Institute of Electrical Engineers of Japan.


Yamamoto K.,Kobe City College of Technology | Yanagawa S.,Shoden Co. | Sekioka S.,Shonan Institute of Technology | Yokoyama S.,Japan Central Research Institute of Electric Power Industry
IEEJ Transactions on Electrical and Electronic Engineering | Year: 2010

In order to exploit high wind conditions, wind turbine generator systems are often constructed in places where few tall structures exist; therefore, they are often struck by lightning. Much of the damage caused by lightning is from the resulting breakdown and malfunction of the electrical, communication, and control systems inside the wind turbine generator system; these breakdowns can be attributed to a rise in electric potential both within the system and in the surroundings due to lightning. Impulse tests were conducted on a wind turbine generator system at a disposal site where the conductivity of the ground was very low, like that found on the surface of the sea. The rise in ground potential of the system, and around its foundation, was measured. When a wind turbine generator system is constructed at a site where the grounding resistivity is very low, the potential rise at the wave front typically becomes larger than that of the steady state because of the inductivity of the grounding system. Therefore, it is very important that the transient characteristics of the grounding system are well understood. © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.


Yamamoto K.,Chubu University | Yanagawa S.,Shoden Co.
2012 31st International Conference on Lightning Protection, ICLP 2012 | Year: 2012

Lightning damage to facilities inside or in the vicinity of wind turbines becomes remarkably common. Most of the breakdowns and malfunctions of the electrical and control systems inside or in the vicinity of wind turbines are caused by ground potential rise due to lightning current flowing into the grounding system of the turbine. To clarify the transient characteristics of the wind turbine grounding systems and to understand the mechanism of the breakdowns and malfunctions, we have carried out field tests. In this paper, the measurements of transient grounding characteristics carried out at wind turbines are descried. © 2012 IEEE.

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