Secondary Test; Check The Activation Of The Voltage Control Operation - ABB RET670 Installation And Commissioning Manual

Section 13
Verifying settings by secondary injection
13.11.4.1
13.11.4.2
184
Terminology
The busbar voltage UB is a shorter notation for the measured voltages Ua, Ub, Uc
or Uij, where Uij is the phase-phase voltage, Uij = Ui -Uj, or Ui, where Ui is one
single-phase-to-earth voltage.
I is a shorter notation for the measured load current; it is to be used instead of the
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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/Setting Group N/
Control/TransformerVoltageControl(ATCC,90)/VCSx/VCPx/
Time/t1 and t2l.
For cases where single-mode voltage control is implemented, the Parameter Setting
menu structure includes VCS1 instead of the parallel designator VCP1.

Secondary test

The voltage control function performs basic voltage regulation by comparing a
calculated load voltage (U
(with upper and lower limits U2 and U1 respectively). The calculated load voltage
U represents the secondary transformer bus voltage UB adjusted for Load drop
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compensation (LDC) where enabled in settings.
Note that when LDC is disabled, UB equals U
When the load voltage U
will be taken.
If U < U1 or U > U2, a command timer will start, which is constant time or
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inverse time defined by 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
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command timer expires, the voltage control will execute a raise or lower command
to the transformer tap changer. This command sequence will be repeated until U
is brought back within the inner deadband range.

Check the activation of the voltage control operation

) against a voltage range defined by setting UDeadband
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stays within the interval between U1 and U2, no action
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1MRK 504 088-UEN C
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Installation and commissioning manual
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