ABB RELION REX640 Technical Manual page 1030

Protection functions
the circle is shifted to the right of the X-axis and if the sign is negative, the circle
is shifted to the left of the X-axis. For an origin-centric mho characteristic,
enable is kept disabled.
Figure 572: Designing zones with Offset and Displacement
The offset-mho characteristic shown in Figure
value for
Timer
Once activated, the Timer activates START output. The time characteristic is
according to DT. When the duration of the underimpedance condition exceeds the
set definite
locus moves out of circular operating characteristics before the module operates,
the reset timer is activated. If the reset timer reaches the value set by
time , the operating timer resets and the START output is deactivated.
The Timer calculates the start duration value START_DUR, which indicates the
percentage ratio of the start situation and the set operating time (DT). The value
is available in the Monitored data view.
1030
When using the mho-characteristics, the
settings are as given in the UEXPDIS function, but
UEXPDIS Diameter setting.
X (Reactance) pu
Offset
Displacement
Operating Region
Offset and a negative value for Displacement .
More than one impedance value is available when
mode is set to "3Phase-phase", and the function considers the lowest
impedance value for starting and operating.
Operate delay time , the OPERATE output is activated. If the impedance
Offset and Displacement
R (Resistance) pu
Polar reach
Figure 572
1MRS759142 F
Offset
Polar reach is half of
is designed with a positive
Impedance Meas
Reset delay
REX640
Technical Manual