ABB RET650 Applications Manual page 232

Section 11
Control
226
TotalBlock: When this setting is On the voltage control function, TR1ATCC for
single control and TR8ATCC for parallel control, is totally blocked for manual as
well as automatic control.
AutoBlock: When this setting is On the voltage control function, TR1ATCC for
single control and TR8ATCC for parallel control, is blocked for automatic control.
Operation
FSDMode: This setting enables/disables the fast step down function. Enabling can
be for automatic and manual control, or for only automatic control alternatively.
tFSD: Time delay to be used for the fast step down tapping.
Voltage
UseCmdUSet: This setting enabled makes it possible to set the target voltage level
via IEC 61850 set point command. This, in turn, makes the setting USet redundant.
USet: Setting value for the target voltage, to be set in percent of UBase.
UDeadband: Setting value for one half of the outer deadband, to be set in percent
of UBase. The deadband is symmetrical around USet, see section
voltage control for a single
equal to DU. The setting is normally selected to a value near the power
transformer's tap changer voltage step (typically 75 - 125% of the tap changer
step).
UDeadbandInner: Setting value for one half of the inner deadband, to be set in
percent of UBase. The inner deadband is symmetrical around USet, see section
"Automatic voltage control for a single
UDeadbandInner is equal to DU
Typically the inner deadband can be set to 25-70% of the UDeadband value.
Umax: This setting gives the upper limit of permitted busbar voltage (see section
"Automatic voltage control for a single
of UBase. If OVPartBk is set to Auto&ManBlock, then busbar voltages above
Umax will result in a partial blocking such that only lower commands are
permitted.
Umin This setting gives the lower limit of permitted busbar voltage (see section
"Automatic voltage control for a single
of UBase. If UVPartBk is set to Auto Block orAuto&ManBlock, then busbar
voltages below Umin will result in a partial blocking such that only raise
commands are permitted.
Ublock: Voltages below Ublock normally correspond to a disconnected transformer
and therefore it is recommended to block automatic control for this condition
(setting UVBk). Ublock is set in percent of UBase.
transformer", figure 71. In that figure UDeadband is
transformer",figure 71. In that figure
. The setting shall be smaller than UDeadband.
in
transformer", figure 71). It is set in percent
transformer", figure 71). It is set in percent
1MRK 504 169-UEN A
"Automatic
Transformer protection RET650 2.2 IEC
Application manual