Circulating current voltage regulation
SEMOD175185-775 v7
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/IED Settings/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,
•
T1RXOP
and
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
,
T2RXOPnot
in
IED
T2
and so on.
3.
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.
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/IED Settings/TransformerVoltageControl(ATCC,90)/
TR1ATCC:x/TR8ATCC:x/Time/t1 and t2
5.
Inject a voltage U
B
equal to
USet
for each transformer.
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.
7.
Confirm that a circulating current is measured on the local HMI that is equal
in magnitude to 5% of
I2Base
, with polarity as discussed in step
.
8.
Confirm the settings for C
i
(Compensation Factor) and X
i
(Transformer Short
Circuit Impedance). Using these setting values and the measured quantity of
1MRK 506 377-UEN C
Section 10
Testing functionality by secondary injection
Railway application RER670 2.2 IEC
149
Commissioning manual
Summary of Contents for RELION RER670
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