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