ABB RELION RET670, Commissioning Manual, Page: 259 / 328

, , , , vl im vb im xline il re rline il im
= - × - ×
EQUATION2085-ANSI V1 EN
(Equation 110)
where:
vb
is the complex value of the busbar voltage
il is the complex value of the line current (secondary side)
rline is the value of the line resistance
xline is the value of the line reactance
For comparison with the set-point value, the modulus of U
L
are according to
equation 111 .
¦ V
L
¦ = (vl , re)
2
+ (vl , im)
2
EQUATION2087-ANSI V2 EN
(Equation 111)
4. Inject voltage for V
B
equal to setting VSet .
5. Inject current equal to rated current I2Base .
6. Confirm on the local HMI that service values for bus voltage and load current are
equal to injected quantities.
7. Confirm that the calculated value for load voltage, displayed on the local HMI, is
equal to that derived through hand calculations.
8. When setting OperationLDC set to Enabled , the voltage regulation algorithm uses
the calculated value for load voltage as the regulating quantity to compare against
VSet and the voltage deadband limits VDeadband and VDeadbandInner .
9. While injecting rated current I2Base into the IED, inject a quantity for V
B
that is
slightly higher then VSet + |( Rline +j XLine ) · I
L
|. This will ensure that the regulating
voltage V
L
is higher than VSet , and hence no tap change command should be issued
from the IED.
10. Reduce the injected voltage for V
B
slightly below VSet + |( Rline +j XLine ) · I
L
| and
confirm that the calculated value for load voltage is below VSet and a tap change
command is issued from the IED.
11.10.3.8 Parallel voltage regulation
Master follower voltage regulation
1. For the transformers connected in the parallel group, confirm that OperationPAR is
set to MF .
2. For parallel operation, it is also recommended to confirm for parallel group
membership, defined by setting
TnRXOP in the local HMI under Main menu/
1MRK 504 165-UUS -
Section 11
Testing functionality by secondary injection
Transformer protection RET670 2.2 ANSI 253
Commissioning manual