Uninterrupted power supplies (UPS) emit alarm signals (audible and visual) to alert operators to fault conditions or a change in operating environment. A primary function of uninterruptible power supplies is to monitor the power supply and respond when it is no longer present, or if it fluctuates to extremes outside of predefined boundaries. The point about alarm signals, however, is that they are only useful if someone is there to hear and respond to them. UPS monitoring and how alarms are responded to should be an important part of a Power Continuity Plan, as failure to act will result in reduced system resilience.
A complex, multi-site installation, for example, throws up a number of challenges in terms of how uninterruptible power supplies will be monitored. Each unit will have local, network and remote monitoring and control facilities in place using a combination of built-in communication ports within the UPS itself. In addition, a UPS monitoring system comprises other components including hardware (cabling, connectors, sensors) and software accessories. Monitoring software has been designed to recognise certain pre-defined conditions and can be configured to respond in certain ways, such as perform a controlled sequential and priority-based shutdown of protected equipment in the event of a fault condition or power failure.
Why Monitoring Should be Part of a Power Continuity Plan
Today’s uninterruptible power supply designs contain microchip technology that allows them to perform detailed analysis of electricity voltages and currents and their operating environments. They can even be automated to respond in a certain way to within preset parameters, and shut down all or part of the system. But the technology only goes so far, and as with most critical equipment, there may be a need for human intervention at some point in the decision making process. Classic examples of inadequate monitoring include failure to notice that a UPS is operating in bypass or that it failed a battery test a week prior to a mains power failure.
Today’s uninterruptible power supply manufacturers provide a range of monitoring and control packages from simple installation and service programmes to complete network packages capable of cross-platform communication and external management across the internet or other gateway. Service monitoring packages may also be offered as a supplement to emergency call-outs and remote site monitoring.
Basic UPS installation software, designed to run on laptops, PCs and PDAs can be customised onsite to interrogate alarm and history logs, display information (bar graphs and measurements) and initiate test routines. UPS monitoring and control software is more sophisticated and can provide all of the above plus a graphical display of UPS operating conditions; sequential and priority-based computer and file server shutdown; event scheduling for timed system boot up and power down; alarm message management including email, faxes and SMS and monitoring via a WAP server on a handheld device or internet browser.
Outside of the capabilities of UPS software, onsite monitoring should also include regular and consistent physical and visual inspection of all power continuity equipment, most particularly, UPS batteries and battery cabinets. Alongside the UPS units themselves, it is important to check cabling and connectors for wear and tear or damage.
Remote monitoring enables signals and other information communicated by the uninterruptible power supplies to be transmitted to an offsite service centre via a modem and telephone line (fixed or cellular). This type of platform offers two-way communication; alongside receiving information generated by the power protection equipment, service centre personnel can also dial up the UPS or generator/s to interrogate their status and generate alarm logs and other reports. They can also initiate self-diagnostics to locate the source of a problem and perform certain tests that will highlight problem areas or potential problems such as a depleted battery.
This article was compiled using information available in The Power Protection Guide – the design, installation and operation of uninterruptible power supplies (ISBN: 9 780955 442803). By Robin Koffler and Jason Yates of Riello UPS.