ABB RELION RET670, Applications Manual

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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 within the time tWindowHunt .
NoOpWindow : Setting of the number of contradictory tap changer operations (RAISE,
LOWER, RAISE, LOWER etc.) required during the time window tWindowHunt to
activate the signal HUNTING.
Power
P> : When the active power exceeds the value given by this setting, the output
PGTFWD will be activated after the time delay tPower . It shall be noticed that the
setting is given with sign, which effectively means that a negative value of P> means
an active power greater than a value in the reverse direction. This is shown in figure
376 where a negative value of P> means pickup for all values to the right of the
setting. Reference is made to figure 371 for definition of forward and reverse direction
of power through the transformer.
en06000634_2_en.vsd
P
P>
IEC06000634 V2 EN-US
Figure 376: Setting of a negative value for P>
P< : When the active power falls below the value given by this setting, the output
PLTREV will be activated after the time delay tPower . It shall be noticed that the
setting is given with sign, which effectively means that, for example a positive value of
P< means an active power less than a value in the forward direction. This is shown in
figure 377 where a positive value of P< means pickup for all values to the left of the
setting. Reference is made to figure 371 for definition of forward and reverse direction
of power through the transformer.
en06000635_2_en.vsd
P
P<
IEC06000635 V2 EN-US
Figure 377: Setting of a positive value for P<
Section 15
1MRK 504 163-UUS A
Control
798 Transformer protection RET670 2.2 ANSI
Application manual