ABB Relion 670 Series Commissioning Manual page 190

Section 11
Testing functionality by secondary injection
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 /IED
Settings/Control /TransformerVoltageControl(90, U↕)/TR8ATCC(90, U↕||):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,
•
•
If T1 - T3 are available,
•
•
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 /IED Settings/
TransformerVoltageControl(90, U↕) /TR1ATCC(90, U↕):x/TR8ATCC(90, U↕||):x /Time/t1 and t2
5. Inject a voltage V
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 6.
8. Confirm the settings for Ci (Compensation Factor) and Xi (Transformer Short Circuit Impedance).
Using these setting values and the measured quantity of circulating current from the local HMI
(Icc_i), calculate the value for circulating current voltage adjustment Vci.
Vdi
EQUATION2089-ANSI V1 EN-US
The voltage regulation algorithm then increases (for transformer T2) or decreases (for transformer
T1) the measured voltage by Vdi and compares Vi against the voltage deadband limits V1 and V2
for the purposes of voltage regulation.
Vi VB Vdi
EQUATION2091-ANSI V1 EN-US
184
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).
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.
equal to VSet for each transformer.
B
= × ×
Ci Icc i Xi _
= +
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1MRK 511 403-UUS Rev. K
SEMOD175185-775 v8
(Equation 46)
(Equation 47)
Bay control REC670
Commissioning manual