PCS100 UPS-I
User Manual
17
2.3.2
Utility Disturbance Occurs
When the utility voltage deviates from user defined limits, due to voltage sags, surges, under-voltages, over-
voltages or outage, the PCS100 UPS-I inverters begin supplying power to the load (Discharge mode). At the same
time the utility is disconnected, isolating the PCS100 UPS-
I output and load from the utility. ABB’s own inverter
commutation technique is used to ensure the Util
ity Disconnect SCR’s are commutated off as fast as possible,
minimizing any disturbance to the load.
Legend
Energy Flow
Utility Voltage
PCS100 UPS-I Voltage
Utility Disconnect
SCRs OFF
Inverter
ON
Fail-Safe Bypass
OPEN
Utility
Loa
d
Coupling
Transformer
Utility Voltage
PCS100 UPS-I Voltage
Output
Voltage
Energy Storage
Batteries
or
Ultracapacitors
Figure 2
-
4: PCS100 UPS
-
I energy flow in case of utility supply disturbance
2.3.3
Utility Voltage Returns
When the voltage returns within user defined limits the PCS100 UPS-I synchronizes with the utility voltage then
closes the Utility Disconnect. If required the PCS100 UPS-I can softly transfer the load from the inverter to the
utility or generator using the generator walk-in function. Once the load is transferred, power to the load is again
supplied by the utility. The PCS100 UPS-I energy storage is then rapidly recharged by the inverters.
Legend
Energy Flow
Utility Voltage
PCS100 UPS-I Voltage
Utility Disconnect
SCRs ON
Inverter
ON
Fail-Safe Bypass
OPEN
Utility
PCS100 UPS-I Voltage
Utility Voltage
Coupling
Transformer
Load
Output Voltage
Energy Storage
Batteries
or
Ultracapacitors
Figure 2
-
5: PCS100 UPS
-
I energy flow in case of charging
For detailed information on Energy Storage charging refer to section 9.4.