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Section 11
Testing functionality by secondary injection
8.
When setting OperationLDC set to On, the voltage regulation algorithm uses the calculated
value for load voltage as the regulating quantity to compare against USet and the voltage
deadband limits UDeadband and UDeadbandInner.
9.
While injecting rated current I2Base into the IED, inject a quantity for U
then USet + |(Rline+jXLine) · I
USet, and hence no tap change command should be issued from the IED.
10.
Reduce the injected voltage for U
the calculated value for load voltage is below USet and a tap change command is issued from
the IED.
11.11.5.8
Parallel voltage regulation
Master follower voltage regulation
1.
For the transformers connected in the parallel group, confirm that OperationPAR is set to MF.
2.
For parallel operation, it is also recommended to confirm for parallel group membership,
defined by setting TnRXOP in the local HMI under Main menu/Settings/IED Settings/Control/
TransformerVoltageControl(90, U↕) /TR8ATCC(90, U↕||):x /ParCtrl
The general parallel arrangement of transformers are defined by setting TnRXOP to On or Off.
The following rules are applicable on the settings T1RXOP – T4RXOP.
If IED T1 and T2 are connected,
•
•
•
3.
The lowest transformer number in the parallel group is by default set as the Master – confirm
that this is the case by reviewing the setting in the local HMI.
4.
Review the settings for UDeadband (based on percentage of nominal bus voltage) and
calculate the upper (U2) and lower (U1) voltage regulation limits for which a tap change
command will be issued from the master transformer in the group.
5.
Review the expected time for first (t1) and subsequent (t2) tap change commands from the
master transformer in the local HMI under Main menu/Settings /IED Settings/Control /
TransformerVoltageControl(90, U↕)/TR1ATCC(90, U↕):x/TR8ATCC(90, U↕||):x /Time/t1 and
t2
6.
Apply a voltage 1% below U1 and wait for the issue of a raise command from the voltage
control after the expiry of a constant or inverse time delay set by t1. Detection of this command
will involve locating the allocated binary output for a raise command in the Signal Matrix in
PCM600 and monitoring a positive from this output. Confirm the timing of this command
correlates with the setting t1.
7.
After the issue of the raise command, confirm that all follower transformers in the group change
tap in accordance with the command issued from the master transformer.
8.
Inject a voltage U
and wait for the issue of a lower command from the voltage control after the expiry of a
constant or inverse time delay set by t2.
9.
Confirm that all follower transformers in the group change tap in accordance with this
command.
Circulating current voltage regulation
This instruction for confirmation of circulating current voltage regulation assumes two transformers in
the parallel group. Setting confirmation through secondary injection requires calculation of circulating
currents for each transformer based on impedance values and respective compensating factors, and
is therefore more complex for greater than two transformers.
246
L
T1RXOP shall be set to On in instance 2 of TR8ATCC,
T2RXOP shall be set to On in instance 3 of TR8ATCC,
T2RXOP and T3RXOP shall be set to On in instance 1 of TR8ATCC, and so on.
The parameter corresponding to the own IED must not be set. T1RXOP should
thus not be set in IED T1, T2RXOP not in IED T2, and so on.
for the master transformer that is 1% above the upper deadband limit U2
B
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|. This will ensure that the regulating voltage U
slightly below USet + |(Rline+jXLine) · I
B
1MRK 504 165-UEN Rev. K
that is slightly higher
B
is higher than
L
| and confirm that
L
SEMOD175185-714 v2
SEMOD175185-716 v8
SEMOD175185-775 v8
Transformer protection RET670
Commissioning manual
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