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/Setting group N/
Control/TransformerVoltageControl(ATCC,90)/TR8ATCC: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,
•
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.
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/Setting group N/
Control/TransformerVoltageControl(ATCC,90)/TR1ATCC:x/TR8ATCC: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
B
for the master transformer that is 1% above the upper deadband limit
U2 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
SEMOD175185-775 v6
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.
1.
Confirm that
OperationPAR is set to CC for the transformers in the parallel group.
2.
For parallel operation, it is also recommended that settings be confirmed for parallel
group membership, governed by setting
TnRXOP in the local HMI under Main menu/
Settings/Setting group N/Control/TransformerVoltageControl(ATCC,90)/TR8ATCC: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,
•
T1RXOP shall be set to On in instance 2 of TR8ATCC, and
•
T2RXOP shall be set to On in instance 1 of TR8ATCC.
If
T1 - T3 are available,
1MRK 502 067-UEN B
Section 12
Testing functionality by secondary injection
217
Commissioning manual
