Power Protection – when you need it most
Uninterruptible power supplies provide a valuable source of back-up power in the event of a mains power supply failure. They allows businesses to ride through short-duration interruptions and power problems; enable a controlled shutdown of non-critical systems and offers sufficient electrical energy to power loads whilst a back-up generator starts up.
Power Conditioning – save on repair and protect data
The voltage of raw mains power can fluctuate wildly, causing power problems such as surges , spikes and transients that are harmful to electrical equipment, particularly servers. Important for data centre and server farm environments is the fact that UPS monitor and condition mains power supply, keeping it to within acceptable levels and negating these harmful problems, thus saving on costly replacement or repair and data loss or corruption.
What do I need to know before selecting an Uninterruptible Power Supply?
Selecting UPS for datacentres and server farms can seem a daunting task but it can be simplified with a preliminary review of the situation (as it is now) and requirements - for now and into the future. What is most needed in datacentres and server farms is:
- Maximum uptime, system resilience and efficiency.
- Low running costs.
- Low energy consumption.
- High density.
- Small footprint.
Sizing Loads For Power protection
To achieve this, firstly, load power requirements must be determined and this can be confusing. On rear panel labels and in user manuals, hardware manufacturers often rate power usage unrealistically high. It is not uncommon to see loads running at only 50% of this. In addition, any ratings given may be in Amps or Watts. There can also be a difference between in-rush (start-up) and running power.
It is important, therefore, when sizing UPS to carefully consider: apparent power (VA – a unit of measure for the apparent power drawn by an electrical device); active power (Watts – a measure for the real power or active power dissipated by the load) and Power Factor (pf – sometimes referred to as displacement power factor or phase power factor. It is the ratio of real power to apparent power in an ac circuit. The higher the input power factor, the more efficient the UPS will be.
The next item to consider is runtime , specifically how much is required? Special consideration must be given to load category and type. Load category determines how critical a load is to the continuity of the business. Critical and essential loads need extended runtime and some form of redundancy. Non-essential loads (canteen facilities or printing services, for example) may need a solution to power emergency lighting (for health and safety whilst they are being shutdown for the duration of the power cut) but no extended runtime. Runtime is load dependent: the bigger the load, the more power it will need to keep it going through a mains power failure. The ‘type' of load is linear or non-linear; inductive, capacitive or resistive, depending on how it draws its current from mains power supply, and this will have a baring on UPS size.
A crucial consideration for datacentres and server farms is density. Rack space ought to be maximised for revenue-earning servers, not UPS and batteries. But without UPS and batteries, 100% uptime cannot be guaranteed. The question needs to be asked as to how much space can be offset to the UPS solution. More importantly, specifiers in these areas should look for newer UPS models that offer the highest power protection and the smallest possible footprint.
Datacentres and server farms are fast-moving environments where growth and expansion are constant. When choosing a UPS solution for today, tomorrow is just as important. The potential for load and runtime expansion must also be thought through. The most common approach is to ramp-up load size by 25% to allow for the next five years' expansion. For online uninterruptible power supply designs (above 10kVA) this can be achieved using parallel architectures.
Contact us if you want to know more about selecting a uninterruptible power supplies and power protection systems for datacentres or server farms.