Establishment of investigation method on lightning damages of home electric appliances and development of lightning protection measures for information oriented society

Change of damage ratio of household appliances related to working circumstance

Photo.1 Change of damage ratio of household appliances related to working circumstance

Change of Damage Ratio

Fig.2 Change of Damage Ratio

Damage of IC Board in Power Supply for Video Set

Photo.1 Damage of IC Board in Power Supply for Video Set

Damages of home electric appliances due to lightning increased in the 1980s when control circuits with micro computers was introduced in them. Home electric appliances became more sensitive to the lightning over-voltages because they were operated at lower voltage and electronic circuits of them were arranged denser than previous ones. Moreover the wide spread of high performance telephones and facsimile machines with not only a power wire but also a communication wire results in the increase of invading routes for lightning surges. The increase of damages of home electric appliances can be attributable to the progress of electronic circuits working at low voltage and the complex arrangement of indoor wiring.
This investigation technique was developed through the investigations on lightning damages of home electric appliances, which has been done 4times from 1987 through 2006.
Using the developed investigation method, the following results on lightning damages of home electric appliances can be obtained.
The outage rate of TV sets is the most for the first investigation from 1987 through 1988. Second investigation, which was done from 1996 through 1997 at the beginning of the information oriented society, revealed that the outage ratio of telephones and facsimile machines increased rapidly. In addition the outage rate of water heaters became large. The investigation from 2004 through 2006, when the information oriented society has fully developed, showed that the outage of personal computers increases tremendously.
The rate of damaged households out of monitors ( % /household /year) was around 0.6% in 1980 s as well as 1990s. On the other hand, it is over 2% in 2006, when the society has become the fully developed information one.
Basic problems related to the rapid increase of lightning damages are lack of regulations and that of testing methods on lightning protection for highly developed electronic circuits and complicated networks. Hosokawa and Yokoyama have clarified that the improvement of lightning surge immunity and suppression of invading surges into inner circuits are most important for reducing lightning damages of home electric appliances.

In order to praise distinguished achievement, IEEJ conferred Progress Award on Takeshi Hosokawa, Shigeru Yokoyama, Nobuhiro Watanabe, Tikashi Okabayashi and Maki Sakae.


Publications

[1] T. Hosokawa, S. Yokoyama, and T. Yokota, “Study of Damages on Home Electric Appliances due to Lightning”, IEEJ Transactions on Power and Energy, Vol. 125, No. 2, pp. 221-226,2005
[2] T. Hosokawa, S. Yokoyama, and M. Soeda, “Aspect of Home Electric Appliances Damages due to Lightning and Future Problem”, IEEJ Transactions on Power and Energy, Vol. 129, No. 8, pp. 1033-1038,2009

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Electricity & Electric Power
(Fundamental Technology)

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