Because modular power protection and conversion technology has proved so successful in commercial applications , the traditionally more conservative industrial engineers are now increasingly seeking ways to use such technology in industrial applications . The problem , however , is that the terminology associated with this technology can be misleading and marketing spin does little to help .

Industrial power protection applications

Three phase UPSs that are widely regarded as being ‘ truly modular ’ have been around since 2001 in the commercial sector ; however , despite many operational benefits this technology is only just beginning to be accepted in industrial markets . This is largely because of the differences between commercial and industrial users ’ priorities , pressures and the demands on their equipment .

A data centre , for example , is a very dynamic environment that is forever changing and reacting to things like the need for ever higher power density and ever faster IT system performance . To maintain competitiveness a typical data centre must upgrade its IT hardware every three to four years . By contrast , a power station is relatively stable and once the site control , management and telemetry systems are installed they are expected to have a useful working life of 20-25 years . These large differences in the requirements of commercial and industrial applications clearly require two very different approaches to the introduction of new technology .

What is modularity ?

Modularity is the state of being modular and modular is something related to , or based upon , modules so , the big question is , what is a module ?

Whilst there isn ’ t a universally accepted definition of module , most engineers would agree that a module is a self-contained device that performs a specific function so this is the definition we shall use in this article .

Be aware , however , that manufacturers ’ marketing departments often blur the lines between the various technologies and topologies so it is more important to understand what the technology / topology is rather than what it is called .

Modular topologies

Modular UPS topology has developed in three distinct stages : advances in the design of electrical and electronic components , particularly surface mount devices , the introduction of Insulated Gate Bipolar Transistors ( IGBTs ), and the invention of the transformerless UPSs allowed modular UPS topology to develop from the traditional mono-block UPS of the 1980s through the modular block architecture of the 1990s to the rack mounted modular UPS that we see today .

Traditional mono block

Most people think of a traditional mono block when describing a UPS . This topology has been around for the past 50 years or more and the single floor standing UPS cabinet contains all of the system components necessary for the UPS to operate . The PCBs , switching components and reactive components are all separate , and individual PCBs and / or components need to be separately removed and replaced in situ to effect a repair . Such repairs are often time consuming , and whilst being repaired the entire UPS is offline and the load exposed to raw mains power .

Furthermore , if additional system capacity and / or redundancy is required after the UPS is installed then the system upgrade ( scalability ) will be expensive , assuming that sufficient floor space and electrical infrastructure is available to accommodate any additional UPS cabinets .

‘ Mono block UPSs are not really a true modular topology .’

A rack mounted modular UPS with individual UPS modules .

Clever marketing spin can argue that , despite their size and weight , each UPS cabinet is a module and therefore the UPS is modular . However , we will see below that mono block UPSs are not really a true modular topology .

38 | November 2016