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1MRK 504 165-UEN Rev. K
11.11.5.1
Secondary test
The voltage control function performs basic voltage regulation by comparing a calculated load
voltage (U
and U1 respectively). The calculated load voltage U
voltage U
When the load voltage U
If U
< U1 or U
L
setting t1 and t1Use. The command timer will operate while the measured voltage stays outside the
inner deadband (defined by setting UDeadbandInner).
If U
remains outside of the voltage range defined by UDeadband and the command timer expires,
L
the voltage control will execute a raise or lower command to the transformer tap changer. This
command sequence will be repeated until U
11.11.5.2
Check the activation of the voltage control operation
1.
Confirm Transformer Tap Control = On and Transformer Voltage Control = On
•
Main menu /Settings /IED Settings /Control /TransformerTapChanger(84,⇅) /
TCMYLTC(84,⇅):x/TCLYLTC(84,⇅):x /Operation
•
Main menu /Settings /IED Settings /Control /TransformerVoltageControl(90,↕) /
TR1ATCC(90, U↕):x/TR8ATCC(90, U↕||):x /General /Operation
•
Main menu /Settings /IED Settings /Control /TransformerTapChanger(84,⇅) /
TCMYLTC(84,⇅):x/TCLYLTC(84,⇅):x /EnabTapCmd
While the test set is connected to the IED but no voltage is applied, the voltage control
functions will detect an undervoltage condition that may result in an alarm or blocking of the
voltage-control operation. These conditions will be shown on the local HMI.
2.
Apply the corresponding voltage
Confirm the analog measuring mode prior to undertaking secondary injection (positive
sequence, phase-to-phase, or phase-to-earth). This measuring mode is defined in the local
HMI under Main menu /Settings /IED Settings /Control /TransformerVoltageControl(90,
U↕) /TR1ATCC(90, U↕):x/TR8ATCC(90, U↕||):x /General /MeasMode
The application of nominal voltage USet according to set MeasMode to the IEDs should cause
the alarm or blocking condition for undervoltage to reset.
11.11.5.3
Check the normal voltage regulation function
1.
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.
2.
Review the expected time for first (t1) and subsequent (t2) tap change commands from the
voltage control function on the local HMI under Main menu /Settings /IED Settings /Control /
Transformer protection RET670
Commissioning manual
) against a voltage range defined by setting UDeadband (with upper and lower limits U2
L
adjusted for Load drop compensation (LDC) where enabled in settings.
B
Note that when LDC is disabled, U
stays within the interval between U1 and U2, no action will be taken.
L
> U2, a command timer will start, which is constant time or inverse time defined by
L
Direct tap change control
Automatic transformer voltage control
Enable Tap Command
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represents the secondary transformer bus
L
equals U
.
B
L
is brought back within the inner deadband range.
L
Section 11
Testing functionality by secondary injection
SEMOD175185-145 v5
SEMOD175185-537 v10
SEMOD175185-562 v7
243
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