ABB REG670 Commissioning Manual page 272

Section 13
Testing functionality by secondary injection
266
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.
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 Enabled or Disabled. The following rules are applicable on the settings
T1RXOP - T4RXOP.
If IED T1 and T2 are connected,
• T1RXOP shall be set to Enabled in instance 2 of TR8ATCC (90), and
• T2RXOP shall be set to Enabled in instance 1 of TR8ATCC (90).
If T1 - T3 are available,
• T1RXOP and T2RXOP shall be set to Enabled in instance 3 of TR8ATCC
(90),
• T2RXOP and T3RXOP shall be set to Enabled in instance 1 of TR8ATCC
(90) and so on.
The parameter corresponding to the own IED must not be set.
T1RXOP should thus not be set in IED T1, T2RXOPnot in IED T2
and so on.
3. Review the settings for VDeadband (based on percentage of nominal bus voltage)
and calculate the upper (V2) and lower (V1) voltage regulation limits for which a
tap change command will be issued from the master transformer in the group.
4. 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/TransformerVoltageControl(ATCC,90)/TR1ATCC:x/TR8ATCC:x/
Time/t1 and t2
5. Inject a voltage V
B
6. Inject a load current for Transformer 1 that is equal to rated load current I2Base
and a load current for Transformer 2 that is equal to 95% of rated load current
I2Base. This will have the effect of producing a calculated circulating current that
flows from HV to LV side for Transformer 1 and LV to HV side for Transformer
2.
Generator protection REG670 2.2 ANSI and Injection equipment REX060, REX061, REX062
equal to VSet for each transformer.
1MRK 502 073-UUS A
SEMOD175185-775 v6
Commissioning manual