17.1.2 Tap changer feedback signal
The feedback signal can be connected when the transformer is equipped with this possibility. A free contact
switch which closes when tap changer movement finalized must be available in the tap changer control box
or transformer control box.
2293 supplies a 3.3V signal, and wait for the returning signal as confirmation that operation is finished.
Connect the feedback contactor of the tap changer
with the “switched” information
3.3V, 1mA (input impedance 100kΩ)
17.2 Tap changer Remote operation
For remote operation of the tap changer, following parameters must be selected.
In the setup button in the function key bar,
select the tap control folder. Then remote
operation and off load tap changer.
Expected time for the tap changer to change
position has also to be introduced (time out)
Once remote operation is selected, the instrument will try to change the position by closing the contacts up
and down, and will wait for the feedback signal to start the new measurement. Procedure is as following
Unit will measure one position and discharge the transformer
The corresponding signal up/down to increase/decrease a position will be sent to the tap changer trough
the tap changer adaptor.
The instrument will wait until the feedback signal come back or the time out expires (whichever happen
first), in addition the tap changer remote control is also equipped with a small switch that will send the
feedback signal to the device manually when pushed.
Steps one to three will be repeated for all positions to be measured.
In case the transformer is equipped with an on-load tap changer, a special operation mode is also available
by selecting the on load tap changer option. During this mode the unit will not discharge the transformer
after the measurement and will continue supplying current while the signal to change position to the tap
changer is sent.
If on load tap changer is selected, and the measuring circuit is interrupted by any reason,
overvoltage will appear in the tap changer contacts that can end in damaging this
component. The on-load operation mode has to be used carefully.
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