ABB Relion 670 Series Applications Manual page 401

1MRK 511 401-UUS F
drive the tap changers apart, which means that the reverse reactance impedance normally needs
to be increased.
Load voltage adjustment (LVA)
LVAConst1 : Setting of the first load voltage adjustment value. This adjustment of the target value
VSet is given in percent of VBase .
LVAConst2 : Setting of the second load voltage adjustment value. This adjustment of the target
VSet is given in percent of VBase .
value
LVAConst3 : Setting of the third load voltage adjustment value. This adjustment of the target value
VSet is given in percent of VBase .
LVAConst4 : Setting of the fourth load voltage adjustment value. This adjustment of the target
value VSet is given in percent of VBase .
VRAuto : Setting of the automatic load voltage adjustment. This adjustment of the target value
VSet is given in percent of VBase , and it is proportional to the load current with the set value
reached at the nominal current
RevAct
OperationRA : This setting enables/disables the reverse action partial blocking function.
tRevAct : After the reverse action has picked up, this time setting gives the time during which the
partial blocking is active.
RevActLim : Current threshold for the reverse action activation. This is just one of two criteria for
activation of the reverse action partial blocking.
Tap changer control (TCCtrl)
Iblock : Current setting of the over current blocking function. In case, the transformer is carrying a
current exceeding the rated current of the tap changer for example, because of an external fault.
The tap changer operations shall be temporarily blocked. This function typically monitors the
three phase currents on the HV side of the transformer.
DayHuntDetect : Setting of the number of tap changer operations required during the last 24 hours
(sliding window) to activate the signal DAYHUNT
HourHuntDetect : Setting of the number of tap changer operations required during the last hour
(sliding window) to activate the signal HOURHUNT
tWindowHunt : Setting of the time window for the window hunting function. This function is
activated when the number of contradictory commands to the tap changer exceeds the specified
number given by
NoOpWindow : Setting of the number of contradictory tap changer operations (RAISE, LOWER,
RAISE, LOWER etc.) required during the time window
HUNTING.
Power
P> : When the active power exceeds the value given by this setting, the output PGTFWD will be
activated after the time delay
effectively means that a negative value of
reverse direction. This is shown in figure
Bay control REC670
Application manual
I2Base .
NoOpWindow within the time tWindowHunt .
tPower . It shall be noticed that the setting is given with sign, which
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tWindowHunt to activate the signal
P> means an active power greater than a value in the
where a negative value of
Section 14
Control
P> means pickup for all
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