Smooth running

Customers expect their data centres to run smoothly, without any interruptions, and those responsible for specifying and managing data centre infrastructure expect the same level of service from their power provider. Here, Ian Wilcoxson, market sector manager – data centre power solutions at Finning Power Systems (Finning), the UK and Ireland’s sole provider of Caterpillar equipment looks at some of the latest issues relating to data centre power

Standby generating power

Data centre operators are faced with a number of concerns relating to power and energy on an almost daily basis, a recent example being the implementation of Phase III of the EU ETS (Emissions Trading System) scheme.

Under the revised Phase III, data centre standby generating power is now a measurable asset for carbon accounting purposes.

The directive is applicable throughout the EU and is quite complex in terms of eligibility criteria. Data centres with greater than 7MW of generating capacity will be affected, and the implications of not being registered on the scheme can be significant. Using generators with Low Break Specific Fuel Consumption (LBSFC) can reduce a customer’s burden under the scheme, and all Cat® generator sets are LBSFC optimised as standard.

Getting the measure of uptime

The Uptime Institute has, for many years recommended that standby gensets should be rated for continuous operation in order to ensure power availability and data centre resilience in the event of a mains outage, stating that:

“Engine generators for Tier III and IV sites shall not have a limitation on consecutive hours of operation when loaded to ‘N’ demand.”

While this provides the necessary assurances of power continuity, it can also be a costly approach, even for those operators that take the less conservative option of opting for a prime rated set.

Not only is equipment specified with a higher rating than necessary under normal operating conditions, it can result in the installation of larger units that take up more valuable data space and may require more frequent servicing and maintenance. At the same time, operators will want to ensure that they comply with the Uptime Institute’s recommendations and the ISO 8528-1 standard in order to achieve the required Tier rating; so deliberate oversizing of gensets has been a routine approach.

Thanks to some work that Caterpillar has undertaken with the Uptime Institute, Finning can now advise that the standard Cat standby and mission critical ratings exceed the parameters referenced in the ISO 8528-1 standard. ISO 8528-1 imposes a runtime limit of 200 hours a year on emergency standby ratings. Cat ratings have a maximum expected usage of 500 hours per year. Further, both ratings state that ‘output is available with varying load for the duration of the outage’ and ‘output is available with varying load for the duration of the interruption of the normal source power.’

This means that a Cat standby or mission critical generator set will provide uninterrupted power for the duration of an outage related to failure of the local utility source – meaning that customers can specify a smaller, more compact genset that is sized closer to the load and still retain the same power resilience that they would get from a larger unit rated for continuous operation. 

Supplying emergency power to flagship facility

Mission critical power installations can vary considerably between applications. Here’s an example of how Finning helped a recent customer to tailor their power requirements to suit their specific needs.

The contract included the supply, installation and commissioning of five, 2.2MVA Cat 3516B-HD generators supported by 72 hours of on-site diesel storage, along with a full power management system to a flagship data centre in Fareham, Hampshire.

The data centre contains 60,000 sq. ft. of pre-configured communal co-location space and private suites. It also contains a further 60,000 sq. ft. of un-configured space that can be precisely customised to individual requirements. The facility uses a modular design, which allows customers to select the level of service that they require.

The data centre is a low-carbon facility that uses a range of energy-efficient technologies to meet stringent environmental targets. Of equal importance is the data centre’s infrastructure and availability to deliver the Tier 3+ subsystem resilience, which includes the site having power availability of at least 99.999%. Power system redundancy is therefore critical to ensure that the load is always fully supported.

In the unfortunate event of a total site power outage, the facility will continue to operate due to the system of N+1, concurrently maintainable standby generators supplied by Finning. The generators offer up to 11,375KVA of prime power, and are capable of providing 12,500KVA (+10%) in an overload condition.

During installation, Finning was able to stack four of the generators on top of each other, allowing the customer to save space for any further units. It was important that service access was taken into consideration during the installation, particularly when getting servicing consumables to the generators in an efficient manner.

In addition to the standby generators, Finning also installed a dual master PLC based power management system (PMS), which included controls for generator protection and synchronising, fuel control as well as outstations for control of mains incoming switchboards.