Aaron Oddy, Sales Engineer at Centiel UK, explains why simply installing the best UPS on the market and calling it a day is not always the wisest decision.
A UPS protects the critical load within all types of facilities. The highest quality, true modular UPS systems will increase availability and resilience whilst removing single points of failure. However, simply installing the very best UPS on the market is not enough to completely mitigate the risk to the critical load. We also need to look outside the UPS box to ensure the surrounding infrastructure also avoids single points of failure.
Considering the overall infrastructure in a new build can be relatively straightforward, however, it may be that you’re installing a UPS into an existing building or an empty room with no infrastructure and that comes with its own unique challenges. The ideal scenario is to create a separate room for the switchgear and batteries. This minimises air conditioning costs as the UPS can run at a higher temperature than VRLA batteries, which need to be kept at around 20-220°C to optimise their design life.
It’s important to work with clients to establish information about the load in order to understand their needs and provide the right configuration for the UPS, as well as the associated infrastructure. Of course, a modular UPS can offer the flexibility, availability and scalability to suit most facilities, but you will still need to understand what the load is supporting, how critical it is and what the load consumption will be. That way you can provide the optimal solution and ensure it is right sized from the outset.
This is especially important as oversized UPS systems cost more to buy, install and run so getting this right from day one will reduce the total cost of ownership for the end-user.
Equally important will be understanding the required resilience of the system. Will an N+1, N+N or 2N+1 configuration be needed? Also, the autonomy or run time of the batteries needs to be considered. This will depend on how long it takes to undertake a graceful shut down to protect servers or to switch over to a generator.
Using an N+N UPS configuration is often a good solution for critical facilities as it introduces duplication and redundancy of systems. Risk can further be mitigated by using an A&B configuration, meaning two separate power supply paths are used, and there is no single point of failure from the power source to the UPS to the load.
If both power supplies come from a single source, loss of mains will cause both UPS systems to run on DC, until mains are restored, or a secondary power supply is provided, for example, a generator.
This extra level of resilience through duplication also needs to be considered for the outputs of the UPS too. For an A&B system, two separate distribution boards will enable one side of the UPS to be isolated for maintenance while the other ensures the load remains fully protected.
For new build installations it’s relatively simple to advise on the best configuration of the UPS and associated infrastructure. For legacy installations perhaps which were installed 10-15 years ago, now ready for lifecycle replacement, the challenges are slightly different as you are often working with ‘what we’ve got’. Here, a careful assessment of the current situation is prudent to see what needs to be changed to mitigate risk to the load during the installation and in the future.
We often find that even though the infrastructure, including the UPS systems have been designed with separate A&B feeds, certain loads may not always have the capability of being dual fed. This introduces single points of failure and puts this critical load at risk. To remove this risk, it is essential that they are fed via fast-acting static transfer switches taking independent supplies from each UPS system. Similarly, a centralised output distribution board can also add a single point of failure into your overall infrastructure, in some cases this is the only option. Be aware that in this scenario, if the UPS needs to be isolated or removed, the shared output board remains live and cannot be maintained unless the load is shut down.
To fully remove risk to the load, everything needs to be duplicated, the mains input supply, the output distribution, and everything associated with the UPS system, including the batteries. Removing all the single points of failure within the surrounding infrastructure is just as important as within the UPS set up itself.
Recently we were presented with a replacement situation that had a centralised infrastructure and no means of bypassing the UPS system. This meant that there was no way of replacing equipment without shutting everything down, which was not an option for the client. Fortunately, we were able to create a safe workaround as the load was fed by dual output distribution.
We partnered with other specialists to supply a temporary containerised energy farm; essentially a mobile solution that can include a UPS and generator which can be deployed to any site. This enables us to provide secure power to the load during the decommissioning of the existing UPS system through to the commissioning of the new. This ensures the load remains supported for the duration of the works.
Working closely with the client and other contractors we scheduled and agreed a timetable of works so everyone on site was prepared for the switch over. Mitigating any risk before the next element of works took place was essential. Here, communication was a key element of a successful installation to ensure risks were identified and timescales established so everyone was comfortable with their area of responsibility.
To remove any risk during future works we installed an external bypass which means, there will be no need to shut down and switch to a temporary power protection for upgrades or any remedial works to the UPS.
For any legacy UPS systems that are being considered for replacement, a comprehensive site survey identifies issues early and enables solutions to be put in place to overcome any challenges which are presented. A facility may appear to have the highest level of resilience but often it is not quite as simple as that! Additional work may be required to ensure the load remains protected during the new installation.
However, a thorough site survey, close collaboration with clients and thinking outside the UPS box, means you can create a future-proofed system which removes single points of failure not only from the UPS but associated infrastructure too, protecting the critical load.