Tokyo. - August 18, 2014 - Meidensha Corporation ("Meiden") (Tokyo Stock Exchange Sticker: 6508, President & C.E.O. Yuji Hamasaki today announced that the gapless metal oxide surge arrester (MOSA) for electric power systems that Meiden pioneered in 1975 was awarded an IEEE Milestone by the Institute of Electrical and Electronics Engineers ("IEEE") Inc., which is the world's largest electrical and electronic scientific association. The award was granted in recognition of the MOSA's improved resistance against multiple lightning strikes and contamination and for making significant contributions toward the development of arresters.

The IEEE Milestone program honors achievements in the field of electricity and electronics technology field that have made historical contributions to the society, and is awarded only after at least 25 years from the development of the technology. Since the milestone program was established in 1983, the award has been given to more than 20 technological achievements in Japan, but Meiden's gapless MOSA is the first in the country to receive the IEEE Milestone for an individual heavy electrical product.

Arresters have the important role of preventing power failures by protecting devices from overvoltage caused by lightning and switch surge.
Arresters in 1950s used gapped silicon carbide (SiC) resistor elements in series and were not sufficiently reliable against multiple lightning strikes and contamination.
Meiden embarked on the development of a zinc oxide (ZnO) element for electric power systems in 1972 and subsequently succeeded in the development of the innovative gapless metal oxide surge arrester (MOSA) using the ZnO element, which eliminated the shortcomings of the conventional arresters. In 1975, Meiden delivered the world's first 66 kV MOSA to Kyushu Electric Power Co., Ltd.
Furthermore, Meiden strived to promote Japanese and international standards for MOSA and the world's first MOSA standards JEC-217 in 1984 and IEC-60099-4 in 1991 were enacted and issued.
Metal oxide surge arrester (generic name) are known around the world as a purely Japanese technological innovation related to electric power equipment and currently this innovative technology is the mainstream technology for surge arresters in the entire power-related fields (power station and substation, distribution and transmission) around the world.

MOSA

IEEE Milestone

Ceremony

• *About IEEE (The Institute of Electrical and Electronics Engineers, Inc.)
  IEEE (pronounced "eye-triple-e") is the world's largest professional association of electrical and electronic engineers headquartered in the U.S. It has more than 420,000 members in over 190 countries around the world and plays a leading role in the technological fields of electricity, electronics, information and communications.

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