Data Centre UPS Systems

There are several primary issues to cover when planning a data centre ups systems installation. These range from the type of power protection plan to be installed in terms of centralised v decentralised, battery, maintenance bypass and standby power arrangements.

The power protection consultants at Server Room Environments have years of experience in the design, installation and maintenance of data centre UPS. We provide consultancy and project management for new systems as well as upgrades and refurbishment projects, working with several leading UPS manufacturers and suppliers as independent UPS consultants.

Centralised or Decentralised Data Centre UPS

A data centre is a self-contained building dedicated to the provision of IT-server based services. Within the data centre will be a data hall, white space or server room facility that will require uninterruptible power protection. The issue is whether to use a large single UPS system to power the entire data centre or to install multiple uninterruptible power supplies at the server rack or server row level.

A large centralised data centre UPS can be easier to maintain and optimise in terms of energy efficiency. The system will typically be a three-phase input and output UPS with an external maintenance bypass and connected battery set. In a decentralised arrangement individual uninterruptible power supplies can be easier to install but provide more of a longer-term maintenance issue.

In a centralised arrangement it is more common for a redundant N+X UPS system to be installed. The redundancy provides additional capacity or resilience in case of UPS system failure and during preventative maintenance.

Lead Acid or Lithium UPS Batteries

The most common type of battery installed with a UPS system is a sealed lead acid maintenance free battery with a five or 10-year design life. This type of battery is designed for standby power applications and intermittent usage. Lead acid batteries are not tolerant of high temperatures and degrade with performance. Their optimum operation is achieved within a 20-25˚C ambient.

Some UPS manufacturers now offer lithium-ion battery alternatives. This type of battery is more suitable to a more regular and higher number of charge/discharge cycles and is more temperature tolerant. UPS systems installed with lithium-ion batteries have the potential to act as Virtual Power Plants (VPP) allowing the data centre to operate ‘off-grid’ and take part in National Grid demand-side response (DSR) programmes.

Lithium-ion UPS batteries are more costly than traditional lead acid batteries but this can be off-set by their longer design life (10-15 years or more) and potential revenue generation from DSR programmes. Lead acid batteries are easier to recycle with up to 90% of the materials being capable of reclaim for re-use. Recycling services for lithium-ion batteries are less well-established.

UPS Maintenance Contracts and Bypass Arrangements

Within a data centre or server room environment it is rare for systems or the complete facility to be powered down. This means that any UPS systems installed, whether in a centralised or decentralised arrangement will require a form of bypass for maintenance purposes.

UPS systems should be inspected at least annually with some data centre and other high security sites insisting on two UPS preventative maintenance visits per year. Most on-line UPS systems include an internal maintenance bypass. The installation of an external maintenance bypass allows the complete data centre UPS system to be fully isolated and powered down for maintenance, and if necessary, a swap-out

Standby Power Generators

A UPS system is installed with a set runtime battery set. This means that the battery set (whether lead acid or lithium-ion) is sized to provide a number of minutes of back-power at a specific load (kVA/kW). The actual runtime is dependent upon the battery charge state, age and ambient temperature as well as the real-time load size.

Standby power generators provide additional resilience to any UPS systems installation. The generator is typically diesel powered and there are gas-powered alternatives offering more environmentally credentials. The generator will automatically start-up when the mains power fails and provide an alternative source of power to the UPS system to save support its battery set.