Ge DIGITAL ENERGY LP 33 User Manual download pdf (Page 12)

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OPM_LPS_3UO_50K_60K_0US_V010.doc Operating Manual LP 33 Series 50 & 60 kVA

Automatic bypass operation

In VFI (Voltage Frequency Independent) operation

mode, the load is permanently supplied by the

inverter but, in case of trouble on the inverter, or

when overload or short-circuit on the output

occur, if the mains voltage do not exceed the

admitted tolerances, the load is instantly

transferred to the mains through the automatic

bypass, taking advantage of the higher short

circuit power.

Fig. 3.2-3 Energy flow in automatic bypass operation

When the inverter recovers, the load will be re-transferred automatically to the inverter.

In case of parallel system

Each unit has its own bypass.

All the bypasses in the system work together, their control being managed in the same manner by

all units.

The units are continuously exchanging information before taking such decision.

In case the inverter of one unit fails, its bypass remains operating.

It is excluded only if the unit is separated from the common bus by opening its output switch Q1.

Mains recovery operation

As soon as the mains recovers, the rectifier starts

up automatically supplying the inverter and the

battery-charger recharges the battery.

In case the inverter has been shut down following

a complete discharge of the battery, when the

mains recovers the system start up automatically.

Fig. 3.2-4 Energy flow at mains recovery operation

When the energy stored in the battery is sufficient to ensure a minimum time of operation with the

actual load, in case of a future mains failure, the load will be retransferred to inverter (if selected VFI

Mode).

In case of parallel system

When the AC input power recovers, the rectifiers will start up sequentially according to their

number in the parallel system in order to avoid an initial inrush current.

The inverters will start up automatically, but only when the battery has recharged enough for a

minimum runtime with the present load.

When enough inverters to supply the load have been restarted, the load will be transferred from the

automatic bypass back to the inverter bus-bars.

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Ge DIGITAL ENERGY LP 33 User Manual Page 12