By Louis McGarry, Sales and Marketing Director, CENTIEL UK Ltd

It’s hard to get overall statistics for the number of UK power outages each year.   But as I write, the UK Power Network has reported 11 unplanned outages across the nation this morning so far… 

A UPS system protects datacentres from such incidents and also evens out interruptions such as dips and surges to supply clean continuous power.

In August 2019, the UK suffered a significant power outage when two power stations became disconnected from the grid.  Nearly 1 million people lost power and there were reports of transport chaos affecting both England and Wales  However, the story that sticks in my mind is of a hospital in Ipswich, where the back-up generator failed to start due to a faulty battery. As you can see the knock on effect of a power outage can have far-reaching consequences and so the decisions made when developing a power protection plan are critically important.

So often we are presented with simply the power requirement, resilience level and autonomy required to supply a quote.  At the same time we are asked to minimise the budget.  However, being involved earlier, at the design stage of the plan can be of real value for datacentres.  Integrating a UPS system is governed by the rating and load type, whether there is long term secondary backup (i.e. generators) and the available space, which all determines the autonomy.  Generally, when generators are part of the infrastructure, the UPS is used as a bridge to hold the load until the point at which the generator is up and running. So when is the right time for the UPS to hand the load over to generator?

If the plan is carefully thought through, protection can be maximised while costs are minimised.  Take these two scenarios:  Number one, during mains failure do you wait for five minutes before transferring to generator in the hope that mains power returns, avoiding a four pole transfer? Number two, in the event that the generator doesn’t start during mains failure and the UPS is left holding the load, how long would it take to complete a graceful shut down?

Ideally, you don’t want to deplete the batteries completely as then they will not be available when the grid returns, however, sometimes this is unavoidable, so this needs to be added into the autonomy calculation.  Transferring to generator involves a short break in power and therefore a risk, so would it be better to use the UPS and batteries for longer than five minutes to see if the grid returns to full function?  If so, a longer autonomy and more batteries are needed.

These decisions are very individual depending on the nature of the critical load being protected and so the whole plan needs to be tailored accordingly but based on informed decision making. Benjamin Franklin once said “if you fail to plan, you are planning to fail”, so use the experience of our engineers to help you devise a plan at the outset, we can help you to come up with optimal power protection for your datacentre.  Otherwise a simple oversight in the planning process can have the butterfly effect, resulting in a significantly different and unfavourable outcome further down the line. 

Article featured in Mission Critical Power Magazine June 2020

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