There are three types of UPS technology or topology defined by BS EN 62040-3:2011 including online, line interactive and standby/off-line uninterruptible power supplies. Each of the UPS topologies provides a different level of power protection from the basic protection provided by a standby UPS to the intermediate of a line interactive UPS and the ultimate or highest level provided by an online UPS. For help selecting the right solution please contact our projects team.
Static UPS are available in three core topologies, each of which provides a different level of power protection, and classified under BS EN 62040-3 to include:
Inside most modern electronic devices is a switch mode power supply (SMPS). This converts the incoming AC (alternating current) into the levels of DC (direct current) required to power internal circuits and processors. Voltage and frequency fluctuations can stress the SMPS and lead data processing errors, intermittent hardware faults and sudden failures.
UPS systems protect sensitive electronic and electrical devices by providing them with a cleaner, conditioned and regulated power supply and a source of battery backup if there is a power outage or the mains voltage and frequency drifts outside of the input window of the SMPS. The degree of power protection provided by the three UPS topologies varies and can be classified as Ultimate, Intermediate and Basic depending on the topology and level of sophisticated of the device.
The following table summarises the key differences between the UPS topologies:
|UPS Type||Protection Level||Output||Automatic Bypass||Voltage Regulation||No-break Output||Size Range|
|Online||Ultimate||sinewave||yes||yes via the AC-DC-AC process||continuously running inverter||400VA-800kVA, 1MW and larger|
|Line Interactive||Intermediate||sinewave, step wave or square wave*||no||yes with a built-in AVR/AVS||2-4ms||400VA-3kVA|
|Standby/Off-line||Basic||step wave or square wave*||no||no||2-4ms or greater||400VA-1.5kVA|
Note: * product dependent – refer to specification
Static UPS systems are available from 400VA up to 1MW and larger. The systems topologies include monoblock transformerless and transformer-based designs and transformerless modular systems, desktop, tower, rackmount and floor standing. Online UPS systems can act as frequency converters from 50-60HZ or 60-50Hz. 400Hz systems are also available. Transformerless UPS have high operating efficiencies of up to 96% or greater when operated in full online mode. Eco mode type function allows the UPS to reach 99% efficiency.
Some line interactive UPS systems can be installed with battery extension packs that plug into the rear of the UPS. The additional battery backup may be charged by the charging circuit built-into the UPS or may have its own charger and therefore require a separate AC mains power socket.
Online provide longer runtimes, either by replacing the internal battery for a higher Ampere-hour (Ah) rated battery or the use of external battery extension packs. External batteries may be supplied in a battery cabinet or on a battery stand. Provision may have to be made for additional charging if the UPS rectifier does not have sufficient charging capacity for the higher Ah-rated battery set.
UPS systems protect sensitive IT, electronic and electrical devices from mains power problems:
The three UPS topologies differ in how they provide protection from power problems. A standby/off-line UPS provides basic protection i.e. spikes, transients and electrical noise are suppressed to lower levels, the incoming voltage and frequency is tracked until it is either too high or too low form the UPS to power the load without its inverter activating. Online UPS provide a digitally generated sinewave from a continuously running inverter to which the load is always connected during normal operation. If the mains power supply fluctuates or fails the battery set provides DC power to the inverter without a break. Line interactive UPS provide intermediate protection, superior to that of a standby/off-line UPS but not to the high-grade level of an onine UPS.
Rotary UPS differ to static UPS systems and use a continuously rotating mass or motor to generate their electrical power. Rotary UPS systems run from several hundred kVA to Mega-Watt sized installations and require similar project and installation management planning to a generating set.
For more information on the static UPS topologies available from Server Room Environments please contact our projects team.