ABB RET670 Commissioning Manual page 208

Section 10
Testing functionality by secondary injection
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
10. Using the settings for
circuit impedance) calculate the magnitude of Icc
command.
11. Inject current equal to
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.
12. Confirm that a tap change command is issued from the voltage control function to
compensate for the circulating current.
13. 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
4. Review the setting for
an
changer, for parallel control function TR8ATCC (90).
202
> -
2 VB
(Equation 119)
=
(Equation 120)
× × >
_ 2
( )
-
V 2 Vset
>
_
(
Ci Xi
VSet , VDeadband , C (Compensating factor) and Xr2 (transformer short
I2Base for Transformer 1 and ( I2Base - |Icc_ i |) for Transformer 2 so that
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 .
CircCurrBk to confirm whether a circulating current limit will result in
Alarm state, Auto Block or Auto&Man Block of the automatic voltage control for tap
(for the purposes of this test procedure)
-
Vset
)
×
_i necessary to cause a tap change
VSet is required for both transformers during
1MRK 504 154-UUS B
(Equation 121)
(Equation 122)
SEMOD175185-841 v6
Commissioning manual