80 kVA - 130 kVA UPS
User’s and Installation Manual
1017397
Revision D (update)
7
Harmonic Control™ with the IGBT rectifier
Harmonics cause deviations to the power quality (perfect sinusoidal waveform) and are
present in current, voltage or both. Filtering is currently the most common method
used to limit the effects that harmonics present to the rest of the system. Traditional
filters consist of tuned series L-C circuits.
The advanced IGBT rectifier technology of PW9340 UPS modules reduce input
harmonic content down to 3%. This leads to more reliable system operation and more
economic generator sizing as losses in the generator windings are minimised. The
benefit with the practically unity input power factor are the minimised maintenance,
cabling and fusing costs. Moreover, the UPS saves installation space and investment
cost because no additional filters are needed.
Harmonic currents and voltages cause the following:
•
Additional losses in wires and cables
•
Extra heating of transformers and generators with shortened service life
•
False circuit breaker tripping and malfunction
•
Erratic operation of computers, telecommunication, monitors, electronic test
equipment etc.
•
Resonance with power factor correction capacitors
Advanced Battery Management (ABM)™
ABM monitors the status of the battery and charges it only when the battery needs
charging. The feature is very valuable since most of the time battery does not need any
charging. Hence, the function of ABM system is to prolong the battery life up to 50% on
average. It also monitors that the load never crashes because of bad or defected battery.
The key to long battery life is low corrosion inside the battery. The main cause for
corrosion is current flowing through battery. The more current going through battery,
the shorter the battery life. Current flows through battery when it is discharged or
charged. There is very little that can be done for discharging, because it depends on
number of power outages in utility line. However the charging can be controlled and
initiated on the following occasions:
- When turning the unit on using the on/off switch.
- After 18 days without charging
- If the open cell voltage decreases below predetermined voltage level.
Traditional UPS charges batteries continuously. This means that there is current going
through batteries all the time and this causes corrosion. In a traditional on-line the
inverter also causes ripple-current to be fed to batteries causing corrosion.
Hot Sync™ for parallel UPS systems
A parallel UPS system means the linking together of two or more UPS units in parallel
so that in the unlikely event one fails the other can automatically take up the load.
Traditionally a parallel redundancy configuration is achieved by having a common
paralleling logic circuitry in the system. This logic circuitry gives out individual
commands to all the different units. Unfortunately this can lead to a single point of
failure for the whole system because if the logic circuitry system fails the whole UPS
system will be in trouble.
