Gary Jameson, Country Manager: South Africa, Eaton Power Quality, says while blackouts seem to be a thing of the past in South Africa - at least for now - the losses suffered by businesses across the country remain fresh in the mind. The power crisis taught important lessons, the most important being that businesses have to create an environment conducive to protecting their technology investments.
”The key to disaster recovery and business continuity today is operational resilience. In many companies, disaster recovery centres rely on backup centres for their IT business continuity. The key to disaster recovery is, however, not just redundancy; the resilience of the system or the networks is critical.”
Resilience must be incorporated into the technology at the design stage to ensure continuity, even during extended power surges, which may be caused either by power supply inconsistencies or by latent design defects in the electrical and mechanical support systems of the data centre.
In order to achieve a high level of resilience with a UPS system, units with dual conversion design must be used. In this way, the critical IT load is protected against any power quality issues at the input of the UPS, whether it is voltage or frequency related. It is important to note that some of the rotary UPSes, and a small percentage of static UPSes, may not be of dual conversion design.
Static type UPSes utilise battery banks to ensure adequate backup time to provide cover during a mains loss or poor quality from the utility supply. This allows enough time for the standby generators to fire up and support the UPSes.
“For large data centres, it is worth using 10-year design life batteries. It is also necessary to install a battery monitoring system that is based on impedance-check technology. However, it is very likely that in few years time, battery banks will be replaced with fuel cell technology. Battery autonomy can be based on requirements set by the client, but 10 to 15 minutes is the common figure found in this type of industry. Standby generation is also essential for long outages and also to support non-essential loads, like air conditioning, lighting, and so on,” Jameson says.
He adds that since the growth of blade servers, it is good to have generator sets that have excellent compatibility with leading power factors imposed by these servers. This will provide added resilience in the event of the entire UPS system going into bypass mode during a main's loss situation. Since most of the IT loads generate harmonics, it is good practice to limit propagation of such pollution by using active harmonic filters.
“Every business interruption, whether a commonplace power outage or an unexpected natural disaster, strains business operations and can temporarily throw an organisation into chaos,” Jameson concludes. “It remains good practice to evaluate the power quality status of your business, to know what is at risk and to take the necessary steps to keep your business going during a power cut or any other unexpected scenario.”
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