ABB RET650 Series Commissioning Manual page 86

Section 7
Testing functionality
8. To cause a tap change, the calculated value for circulating current voltage adjustment must
offset the injected quantity for bus voltage VB so that Vi is outside the voltage deadband
created by setting
Vdi V
EQUATION2093-ANSI V1 EN-US
VB Vset
EQUATION2095-ANSI V1 EN-US
Therfore:
Ci Icc i Xi V
EQUATION2097-ANSI V1 EN-US
Icc i
EQUATION2099-ANSI V1 EN-US
9. Using the settings for
circuit impedance) calculate the magnitude of Icc
command.
10. Inject current equal to
selected with setting
for Transformer 2 so that the magnitude of calculated circulating current will cause a raise
command to be issued for Transformer 2 and a lower command for Transformer 1.
Magnitude and direction of circulating currents measured for each transformer can be
observed as service values on the local HMI and raise/lower commands detected from the
binary output mapped in the Signal Matrix.
11. Confirm that a tap change command is issued from the voltage control function to
compensate for the circulating current.
12. Injected currents can be reversed such that the direction of calculated circulating currents
change polarity, which will cause a lower command for Transformer 2 and a raise command
for Transformer 1.
Circulating current limit
1. Confirm that
2. Confirm that
3. Review the setting for
80
VDeadband . Expressed by equation
> -
2 VB
(Equation 31)
=
(Equation 32)
× × > -
_ 2
( )
-
V 2 Vset
>
_
(
Ci Xi
VSet , VDeadband , C (Compensating factor) and Xr2 (transformer short
IBase (for winding 2, which is defined in a global base function,
GlobalBaseSel2 for TR8ATCC, 90) for Transformer 1 and ( IBase - |Icc_ i |)
The voltage injection equal to
this test.
OperationPAR is set to CC for each transformer in the parallel group.
OperCCBlock is set to Enable for each transformer in the parallel group.
CircCurrLimit .
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(for the purposes of this test procedure)
Vset
)
×
_i necessary to cause a tap change
VSet is required for both transformers during
1MRK 504 136-UUS B
31 and equation 32.
Transformer protection RET650
Commissioning manual
(Equation 33)
(Equation 34)
SEMOD175185-841 v5