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 Utility Disconnect SCR’s are commutated off as fast as possible,
minimizing any disturbance to the load.
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.
Figure 2-5: PCS100 UPS-I energy flow in case of charging
For detailed information on Energy Storage charging refer to section 9.4.
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