72.5-kV
Dry Air Insulated Dead Tank Type VCB
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We have developed
and launched SF6 (sulfur hexafluoride) gas-less 72.5-kV class
tank type vacuum circuit breakers. These circuit breakers are
the first in the world in this voltage class to realize effective
performance with no use of SF6 gas at all. SF6 gas has a high
global warming coefficient. Although SF6 gas is harmless and
stable, and has high electrical insulation ability, its global
warming coefficient is about 23,900 times higher than that
of CO2 (carbon dioxide). In 1997, a resolution to reduce the
emissions of many kinds of greenhouse effect gas was adopted
at the Kyoto conference (COP3). Since the conference, diminishing
the emissions of SF6 gas has been an important matter in the
world. Conventional vacuum circuit breakers use 0.15-Mpa SF6 gas. These vacuum circuit breakers use dry air pressurized
to 0.45 Mpa and high-voltage electric conductors covered by
certain insulated materials in order to achieve almost the
same level of electrical insulation ability as that of conventional
vacuum circuit breakers, as well as a compact structure. In
addition, the circuit breakers use improved vacuum interrupters
originally developed by us for withstanding high air pressure.
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| Other equipment |
1.
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Hybrid Molded Transformers |
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A noise reducer is integrated into these molded transformers.
As transformer capacity has recently been increasing, noise
reduction is assuming more and more importance. Using the
best coil structure and noise reducer (filter), we have
developed large-capacity hybrid molded transformers (with
a capacity of 10 kVA or more), which are in great demand. |
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2.
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7.2-kV class Vacuum
Circuit Breakers with Permanent Magnetic Actuator |
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The circuit breakers save space and energy and provide
high performance to meet the needs of switchboard manufacturers.
The circuit breakers, consisting of 80% fewer parts than
conventional circuit breakers, are so small and light that
they can be easily installed on a thin switchboard. They
are the lightest of all circuit breakers of this class
(the body weight is 20 kg). |
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3.
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275-kV class Polymer Housed
Arrester |
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This arrester substitutes a composite housing (a high-strength
fabric-reinforced plastic insulation pipe coated with highly
water-repellent and weather-resistant silicone rubber)
for a porcelain insulator. Moreover, it consists of alternately
disposed larger-diameter and smaller-diameter fins to reduce
the pitch between them. Because of these kinds of improvements,
this arrester is by far smaller, lighter, and more quakeproof
than conventional arresters. |
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