•
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.
Inject a voltage UB equal to
USet
for each transformer.
5.
Inject a load current for Transformer 1 that is equal to rated load current
IBase
(for winding 2, which is defined in a global base function, selected with
setting
GlobalBaseSel2
for TR8ATCC) and a load current for Transformer 2
that is equal to 95% of rated load current
IBase
(for winding 2, which is
defined in a global base function, selected with setting
GlobalBaseSel2
for
TR8ATCC). 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.
6.
Confirm that a circulating current is measured on the local HMI that is equal
in magnitude to 5% of
IBase
(for winding 2, which is defined in a global base
function, selected with setting
GlobalBaseSel2
for TR8ATCC), with polarity
.
7.
Confirm the settings for C
i
(Compensation Factor) and X
i
(Transformer Short
Circuit Impedance). Using these setting values and the measured quantity of
circulating current from the local HMI (I
cc_i
), calculate the value for
circulating current voltage adjustment U
ci
.
_
Udi Ci Icc i Xi
=
×
×
EQUATION2088 V1 EN
(Equation 10)
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.
Ui UB Udi
=
+
EQUATION2090 V1 EN
(Equation 11)
8.
To cause a tap change, the calculated value for circulating current voltage
adjustment must offset the injected quantity for bus voltage UB so that Ui is
outside the voltage deadband created by setting
UDeadband
. Expressed by
.
Section 6
1MRK 504 126-UEN -
Testing functionality
72
Commissioning Manual