DKG-329 User Manual V-12
(09.10.2012)
- 12 -
The unit has two ways of transferring the load from genset to mains and vice versa.
These modes are:
-transfer with interruption.
-no break transfer.
This is the most conventional way of transferring the load between the genset and mains. There
will be a power interruption period duration during the transfer. Note that the program parameters
Mains
Contactor Timer
and
Genset Contactor Timer
define the power interruption period.
Transfer from genset to mains:
-The generator contactor releases,
-The unit waits for Mains Contactor Timer
-The mains contactor is energized.
Transfer from mains to genset:
-The mains contactor releases,
-The unit waits for Genset Contactor Timer
-The generator contactor is energized.
In this mode, the transfer will be made
without power interruption
. This implies that both of
the mains and generator contactors will be active during transfer.
The maximum duration that both contactors will be activated is programmable. However this
process may be quicker with the use of one auxiliary contact at each contactor. Thus the changeover
will be quite instantaneous, preventing any excess or reverse power condition. Any digital input can be
programmed for genset contactor auxiliary contact and mains contactor auxiliary contact.
To prevent a phase to phase short circuit below criteria must be met:
-The mains and generator voltages must be equal,
-The mains and generator voltages must have the same phase,
-The mains and generator voltages must have the same phase sequence order.
The unit will allow a
No Break Transfer
only if
all
of the below conditions are fulfilled:
-Mains phase voltages within the programmed limits,
-Mains frequency within the programmed limits,
-Genset phase voltages within the programmed limits,
-Genset frequency within the programmed limits,
-Mains phase order correct (or phase order check must be disabled),
-Genset phase order correct (or phase order check must be disabled),
-The difference between mains and genset frequencies not more than programmed limit,
-The voltage difference between mains_L1 and genset_L1 not more than programmed limit,
-The phase angle between mains_L1 and genset_L1 not more than programmed limit,
If this transfer method is used, it is advised to make an electrical
interlock between contactors to prevent a phase to phase short
circuit.
6.1 No Break Transfer
6.1 Transfer with Interruption
6. LOAD TRANSFER MODES
