Industrial users relying on so-called uninterruptible power systems (UPSs) to provide a smooth and continuous supply when there is a problem with grid supply may get a rude shock if they have taken a ‘fit and forget’ approach, the Health and Safety Executive (HSE) said in an alert sent to major industries.
The UPS systems kick in during a grid supply failure or other power issue, such as supply spikes, to ensure that industrial users have a continuous and smooth power supply. They can take a variety of forms, from batteries to diesel generators, and many offer a 15-20 year lifetime that may be entirely ‘maintenance free’.
HSE said recent investigations had revealed failures of UPS systems, from various suppliers, at a number of industrial sites. Some failures resulted in a loss of power to industrial control systems, emergency shutdown and emergency mitigation. Other incidents were due to component failures and outdated firmware.
HSE highlighted one failure that led to an unplanned shutdown at a chemical processing plant. When it restarted it resulted in a release of toxic substances.
HSE said the operating and maintenance instructions provided do not say there are components with a lifetime shorter than the 15-20 years of the installation, (batteries, filter capacitors, cooling fans, internal RAM batteries, power cards and control cards). Consequently, “ maintenance schedules were inadequate, leading to a false sense of safety and reliability by end users”.
The HSE warning is not specific about the types of UPS involved but says investigation has revealed localised fires within the systems due to failures of capacitors or batteries.
It says the warning does not apply to non-maintainable UPS systems or to ‘rotatory’ UPS systems that pair a flywheel and diesel generator.
The UPS is a ‘behind the meter’ asset. But the inadequacy of manufacturers’ instructions regarding maintenance over the long term should sound a warning for both buyers and sellers of other types of electrical equipment, which are increasingly being installed by large and mid-scale users so they can become active customers and manage their usage.
Read the full alert here.