ABB rec670 Commissioning Manual page 170

Section 10
Testing functionality by secondary injection
164
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/Setting group N/TransformerVoltageControl(ATCC,90)/
TR1ATCC:x/TR8ATCC:x/Time/t1 and t2
5. Inject a voltage U
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.
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 Uci.
= ×
Udi Ci Icc i Xi _
EQUATION2088 V1 EN
The voltage regulation algorithm then increases (for transformer T2) or
decreases (for transformer T1) the measured voltage by Udi and compares Ui
against the voltage deadband limits U1 and U2 for the purposes of voltage
regulation.
EQUATION2090 V3 EN
9. To cause a tap change, the calculated value for circulating current voltage
adjustment must offset the injected quantity for bus voltage U
outside the voltage deadband created by setting UDeadband. Expressed by
equation 42 and equation 43.
equal to USet for each transformer.
×
1MRK 511 360-UEN A
(Equation 40)
(Equation 41)
so that Ui is
B
Bay control REC670 2.1 IEC
Commissioning manual