ABB RELION REX640 Technical Manual page 1290

Protection related functions
Min operate voltage
Figure 731: Configurable directional setting for Zero seq. volt. (residual voltage)
using the Pol quantity setting
The
in the network. For example, in case of an isolated network,
is set to –90°, and in case of a compensated network,
set to 0° and 60° for solidly grounded systems. In general
selected so that it matches close to the expected fault angle value, which results
in maximum sensitivity.
+180°. The figures show examples of the operating area with RCA set to +60° and
–90°, respectively.
Min Operate voltage
Figure 732: Configurable directional characteristics (RCA =+60˚) for a solidly
earthed network
1290
Characteristic angle/
Max torque line
Forward
area
Min forward
angle
Non-operating area
Max reverse
angle
Min operate current
Backward
area
Characteristic angle setting is done based on method of grounding employed
Characteristic angle can be set anywhere between –179° to
Max reverse
angle
Backward
area
Min reverse
angle
Min operate current
RCA = 0 deg
-U ( polarizing quantity)
0
I ( operating quantity)
0
Max forward
angle
Zero torque line
Non-operating area
Min reverse
angle
-U ( polarizing quantity)
0
RCA=+60 deg
Min forward
angle
I (operating quantity)
0
Forward
Max forward
angle
Zero torque line
1MRS759142 F
Characteristic angle
Characteristic angle is
Characteristic angle is
Characteristic
Angle/ Max torque
line
area
Technical Manual
REX640