Electrical Contracting News (ECN) November 2016 | Page 39
POWER PROTECTION
A modular block
UPS with individual
rectifier and inverter
power modules.
The major benefits of modular block
topology are increased system availability
and system maintainability because it is
much quicker to replace, for example, a
faulty rectifier module than it is to repair
a faulty rectifier on site. Modular block
architecture systems, however, still suffer
from the lack of scalability seen in the
mono block systems.
Whilst modular block topology is a lot
more modular than the traditional monoblock UPS discussed above, and whilst
this is an excellent solution for some
specialist applications, this is also not
really a true modular solution.
Rack mounted modular
Modular block architecture
Developing UPS technology allowed UPS
construction methods to evolve, and
modular block systems began to appear.
In this type of system each floor standing
UPS cabinet still contains all of the UPS
system components in a single cabinet
but the major system components are
grouped together into sub-assemblies that
can be considered modules. For example,
all UPSs have a rectifier, an inverter and
a static switch. In the modular block UPS
the rectifier module(s), inverter module(s)
and static switch module(s) are all selfcontained and can be individually removed
from and/or added to the UPS system.
38-39 Power Protection – Benning.indd 39
In this topology each UPS cabinet
contains independent UPS modules
that are paralleled to form the complete
system. Each module is a complete
and independent UPS functional unit,
which can be removed from or added to
the system without interrupting power
availability to the critical load. The ability
to very quickly remove and/or add modules
into a fully functioning UPS system is
often referred to as hot swap or safe swap
and is one of the ways that this topology
can be identified.
Because UPS modules can be very
quickly and safely exchanged, added
to or removed from a fully functioning
UPS system, this topology maxi