SOLA 4000 - General System Description
1 UPS Assembly
During overload or inverter failure conditions, SSI is switched off and SSB is switched on, providing power supply from a backup source (mains, output of another UPS system, diesel generator set....). By always actuating both switches together for a short
period, an uninterrupted power supply during the switching is ensured. This is an essential condition to reliably meet all power supply requirements for connected sensitive equipment.
The control for each static switch (SSB and SSI) is performed totally independently of each other, thus ensuring that a failure in one static switch does not affect the other.
Switching Conditions, Inverter - Bypass The voltage and frequency of the bypass line have to be within set tolerance limits, and the inverters have to be synchronised with the bypass line.
Under inverter failure conditions:
(i)the UPS switches to bypass operation, for a single unit. (SSB switches on, and SSI off).
(ii)for
(iii)in parallel systems, all units switch to bypass operation together only if the load is more than the rated value for the remaining
If the conditions above for the bypass line and synchronisation are not met:
•the inverter will continue to operate with reduced output voltage under overload conditions, or
•the inverter will stop if an inverter failure occurs. In this second case, the system will:
(i)commutate to a second
(ii)the remaining inverters will take the load in the case of a
(iii)the UPS will commutate to the bypass supply with a very short interruption of 10msec if the supplies are not synchronised, for the case of a single UPS unit.
Under overload conditions, all UPS modules present will switch to the bypass supply, and remain in bypass until the overload is removed.
Switching Conditions, Bypass - Inverter a) The UPS switches automatically back to inverter operation when inverter voltage and frequency are within tolerance limits, the overload has been removed and the inverter is synchro- nised with the bypass line (SSI switches on and SSB off).
b)If the UPS unsuccessfully attempts five times within 3 minutes to switch to inverter operation, the UPS remains in bypass operation and signals an alarm. After pressing the
c)If the UPS remains blocked on bypass operation and a mains failure occurs, the UPS will switch automatically to inverter operation if the inverter voltage and frequency are within tolerance and the inverter is synchronised to the mains.
JUE 401264 | 9 |