Power Solutions Guide
Uninterruptible power supplies are the ultimate power solution for many organisations. UPS systems protect voice and data processing systems, including server racks, virtual PBXs and enterprise wide datacentre operations from the expensive downtime, hardware faults and software errors. When selecting the right UPS system for your application, we recommend a two-stage process:
- Power Quality: how polluted, stable and reliable is the mains supply?
- Runtime Required how long do I need to keep my systems running when the mains power supply breaks or fails?
With answers to these questions it is possible to define the right power solution in terms of whether power quality or power breaks are your overriding consideration.
Power Quality – Mains Power Present
All power protection solutions vary in the levels of protection they can provide. The generic types include:
- Filters: a filter attenuates spikes and electrical noise down to predetermined levels. This is the most basic type of power protection.
- Transient Voltage Surge Suppressors (TVSS): a TVSS clamps/diverts excess electrical energy away from downstream loads. TVSS are superior to filters and can tackle larger surge voltages such as those arising from a local/nearby lightning strike. TVSS are most commonly found within heavy industrial complexes, mobile base stations and remote datacentre operations.
- Automatic Voltage Stabilisers: AVRs or stabilisers as they are known correct sags, surges and brownouts conditions, to predetermined levels within an input voltage window. AVRs are commonly used within remote areas where they are use to power non-computer based systems including fridges and freezers, and larger industrial manufacturing processes. AVRs can be can be electronic or electro-mechanical.
- Power Conditioners: provide superior protection when the mains power supply is present. Conditioners can be transformer or electronic-based. The filter, stabilise and also regulate their output voltages to within reasonably tight specifications suitable for use with ICT-based systems. Some power conditioners also include isolation, in the form of Galvanic isolation – a physical separation of the primary and secondary windings of a transformer. Constant Voltage Transformers (CVTs) are the most common example of a power conditioner with inherent built-in Galvanic isolation.
Power Quality – Mains Power Supply Failures
Uninterruptible Power Supplies (UPS) provide varying levels of protection to mains power problems, based on their design and UPS topology. Three generic types of UPS topology are available:
- On-line double-conversion UPS – ultimate power protection
- Line Interactive UPS – intermediate power protection
- Standby UPS – basic power protection
In terms of power quality, on-line double-conversion UPS offer the ultimate power quality and a ‘break-free’ sinewave output supply. Line interactive are a reasonable alternative but are generally only available up to 2kVA but certain on-line models also offer an optional line interactive mode – known as ECO mode. Standby UPS are designed for desktop and Electronic Point of Sale (EPoS) applications. They include basic filtering and a short duration battery pack.
For long runtimes, most on-line and some line interactive UPS can be installed with additional battery packs. Larger on-line UPS tend to be installed as part of a larger Power Continuity plan with a standby generator.