POWER
The role of modern UPS systems Powering Peace of Mind By Matt Henley, Technical Services Manager, Uninterruptible Power Supplies Ltd
As power demand continues to grow, power capacity is under threat of loss, making mains power disruption an ever more likely occurrence in the future. At the same time, more and more businesses and commercial operations are increasingly becoming dependant on critical electronic equipment to function. Against this background, the need for UPS protection is no longer in doubt. Therefore, the focus has rightly shifted to choosing the best UPS solution for the application. This evaluation is supported by a
Matt Henley makes the case for UPS protection.
recent Uninterruptible Power Supplies Limited industry survey, which sought to discover ICT equipment users’ views and experiences relating to these issues. In the survey, over 75 percent of the respondents experienced a power outage within the last 12 months that required their UPS to protect their critical equipment. Users don’t expect this situation to improve; 78 percent believe that power reliability is going to become a major concern within the next 10 years. Today, office and industrial
equipment invariably needs electrical power to operate. Although the consequences of any power failure depend on the nature of the equipment and its application, they are increasingly likely to be serious or even catastrophic. Computer systems, for example, typically cannot tolerate a power break of even a few milliseconds without failing. The potential threat of such events to business security and possibly human safety stretches far beyond the immediate risk to the computer hardware. Accordingly, facilities managers must appreciate mains power issues, what power protection is and how to apply it as organisations become inexorably more dependent on sensitive electronic equipment.
Power Problems Although power failure events, or blackouts, are obvious threats to on-site equipment, other conditions can also cause problems. Brownouts occur when the mains supply cannot cope with its overall load and the voltage levels reduce, in extreme cases for periods measured in hours. Mains power can
22 NETCOMMS europe Volume II Issue 4 2012
also sag, or drop in voltage level for a few cycles, usually after a large load such as air conditioning or rotating machinery is switched on. Conversely, switch-off of such loads can cause voltage surges, where a voltage increase above normal is sustained for more than one cycle. Spikes are short duration rapid voltage transitions superimposed on the mains waveform by external events such as lightning strikes or switching of high electrical currents. Non-linear loads such as computers, photocopiers, laser
printers and variable speed drives impose harmonics on the mains supply. These can cause a disproportionate rise in current and temperatures, leading to equipment overheating and component failure. Not all on-site equipment is
susceptible to such conditions, but a significant proportion is likely to be. Such equipment is often known as the critical load, partly to reflect its requirement for power that is free of availability or control problems, and
Critical loads can be protected from power problems.
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