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UNINTERRUPTIBLE POWER SUPPLIES
Protecting against
disruptions
By Alan Luscombe, Director,
Uninterruptible Power
Supplies Ltd
www.upspower.co.uk
Data centres need protection
from power aberrations and
the solution is twofold
Today, a typical organisation’s performance is only as good
as its ICT resource, which depends just as critically on the
quality and continuity of its power supply. Accordingly, such
resources, which can range from large data centres to small
IT rooms, are usually protected with a UPS system.
Simply sourcing a UPS of suitable capacity isn’t
necessarily enough to provide the level of protection that
the facility needs. What happens if an extended blackout of
several hours or more occurs? Or if the mains input supply is
subject to elevated levels of electrical noise or interference?
We can start by realising that power supply issues divide into
long-term blackouts of extended duration, and short-term
problems such as transients, noise, brownouts and brief-
duration blackouts.
Long-term blackouts
The long-term blackouts need special consideration because
a UPS alone is never sufficient to guarantee cover. No
matter how much the battery autonomy, a blackout of
longer duration is always a possibility. Some facilities can
tolerate this provided they can shut down safely, but most
– especially if the system is processing online transactions –
must continue running under all circumstances.
If the facility is ‘shutdown tolerant’, then it can survive
with a UPS alone. During short-term blackouts, the UPS
simply switches its inverter to battery power on detection
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