Mission Critical Power

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UNINTERRUPTIBLE POWER SUPPLIES

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he perfect UPS is 100% available, 100% efficient, takes up no space, costs nothing to purchase and does not require maintenance. With this in mind, how close is the new 4th Generation modular UPS technology to perfection, and what else needs to be done to achieve power protection perfection? To answer these questions we need to look at where the industry has come from. Thirty years ago, the only way to achieve redundancy was to install a parallel UPS system. These standalone systems were large. A 60KVA UPS was the size of a double wardrobe and weighed about 600kg. You needed two of these for a parallel redundant system, plus batteries, which were typically at least the same size. The transformers inside were heavy and used copper, which was expensive. The units, typically 1VA, cost £1 to purchase. So a 60KVA UPS cost £60K and again you needed to double up for a parallel system. Usually, efficiency was at best around 85%, and they were limited by a mean time to repair (MTTR) of about eight hours needed to fix a fault. Large, high-loss power components required equally large heatsinks and cooling fans to keep them cool. Environmental concerns and green house gases were also not considered in those days. These systems consumed huge amounts of power, were big and noisy, cost a lot of money and required regular, invasive maintenance and component replacement. In other words, the UPS systems of 30 years ago were far from perfect. In the early 1990s, transformerless technology was pioneered by Filippo Marbach and his design team, radically shrinking the UPS units. While transformerless technology has become mainstream today, at the time, it offered dramatically increased efficiency, decreased size and weight and reduced cost. However, although better power components MCP April 2018

Perfect UPS: how close are we to the holy grail? Centiel managing director Michael Brooks recently presented on ‘How Close to The Perfect UPS is 4th Generation Modular UPS Technology?’ at Data Centre World. He examines whether the latest technology, if correctly configured, can significantly improve both power availability and operating efficiency resulted in improved switching efficiencies and quieter operation, customers looking for system redundancy still required two of these units to ensure a parallel redundant UPS system. It still took hours to fix faults in these single units. Fast-forward to the modular UPS introduced after the millennium and we see further improvements. All the circuitry is contained within each module, making repair more straight forward, and therefore improving availability as well as

reducing system footprint. Today, the fastest growing market sector we see are midrange three phase modular systems. This is because properly configured modular systems simultaneously maximise load availability and system efficiency. Modular systems are increasingly replacing traditional stand alone and parallel systems with the drive for high availability, fast repair and commonality of parts, as well as reduced system footprint. The 4th Generation

modular UPS systems now available, such as Centiel’s CumulusPower, incorporating distributed active redundant architecture (Dara), provide a significant improvement over previous system designs. Each module contains all the power elements of a UPS – rectifier, inverter, static switch, display and, critically, all control and monitoring circuitry. We believe this places it above other current designs that have a separate, single static switch assembly and separate control or intelligence missioncriticalpower.uk