• Tap change timeout duration - effectively the maximum transformer tap change time,
tTCTimeout, available on the local HMI under Main menu /Settings /IED Settings /Control /
TransformerTapControl(84,⇅) /TCMYLTC(84,⇅):x/TCLYLTC(84,⇅):x /tTCTimeout
• Load tap changer pulse duration - required length of pulse from IED to load tap changer,
tPulseDur, available on the local HMI under Main menu /Settings /IED Settings /Control /
TransformerTapControl(84,⇅) /TCMYLTC(84,⇅):x/TCLYLTC(84,⇅):x /tPulseDur
• Transformer tap range, LowVoltTap and HighVoltTap, available on the local HMI under Main
menu /Settings /IED Settings /Control /TransformerTapControl(84,⇅) /TCMYLTC(84,⇅):x/
TCLYLTC(84,⇅):x /HighVoltTap
• Load tap changer code type - method for digital feedback of tap position, CodeType, available
on the local HMI under Main menu /Settings / IED settings /Control /
TransformerTapControl(84,⇅) /TCMYLTC(84,⇅):x/TCLYLTC(84,⇅):x /CodeType
During the installation and commissioning, the behavior of the voltage control functions
for different tests may be governed by a parameter group, available on the local HMI
under Main menu /Settings /IED Settings /Control /TransformerVoltageControl(90,
U↕) /TR1ATCC(90, U↕):x/TR8ATCC(90, U↕||):x. These parameter settings can cause a
Total Block, Automatic Block or Alarm for a variety of system conditions including over
and under voltage, over current and tap changer failure. It is important to review these
settings and confirm the intended response of the voltage control function for different
secondary injection tests.
Terminology
The busbar voltage V
B
is a shorter notation for the measured voltages Va, Vb, Vc or Vij, where Vij is the
phase-phase voltage, Vij = Vi -Vj, or Vi, where Vi is one single-phase-to-ground voltage.
I
L
is a shorter notation for the measured load current; it is to be used instead of the three-phase
quantities Ia, Ib, Ic or the two-phase quantities Ii and Ij, or single-phase current Ii.
Also note that for simplicity, the Parameter Setting menu structures included in the
following procedure are referred to universally as VCP1, for example, Main menu /
Settings /IED Settings /Control /TransformerVoltageControl(90, U↕) /TR1ATCC(90,
U↕):x/TR8ATCC(90, U↕||):x /Time /t1 and t2
For cases where single-mode voltage control is implemented, the Parameter Setting menu structure
includes TR1ATCC:1 instead of the parallel designator TR8ATCC:1.
11.11.5.1 Secondary test
SEMOD175185-145 v5
The voltage control function performs basic voltage regulation by comparing a calculated load voltage
(V
L
) against a voltage range defined by setting VDeadband (with upper and lower limits V2 and V1
respectively). The calculated load voltage V
L
represents the secondary transformer bus voltage V
B
adjusted for Load drop compensation (LDC) where enabled in settings.
Note that when LDC is disabled, V
B
equals V
L
.
When the load voltage V
L
stays within the interval between V1 and V2, no action will be taken.
1MRK 504 165-UUS Rev. J Section 11
Testing functionality by secondary injection
Transformer protection RET670 255
Commissioning manual
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