ABB RELION REX640 Technical Manual page 1291

1MRS759142 F
Characteristic
Angle/ Max
Torque line
Figure 733: Configurable directional characteristics (RCA = -90˚) for an isolated
network
Table 1221: Recommended Characteristic angle setting for different network
Type of network
Compensated network
Solidly grounded network
Isolated network
The
method of neutral-point grounding, so that in an isolated network
angle is –90° and in a compensated network 0°. In addition, Characteristic angle can
be changed via the control signal RCA_CTL, in which case the alternatives are –90°
and 0°. The operation of the RCA_CTL input depends on the
setting.
The Peterson coil or the grounding resistor may be temporarily out of operation. To
keep the protection scheme selective, it is necessary to update the
angle settings accordingly. This is done with an auxiliary input in the relay which
receives a signal from an auxiliary switch of the disconnector of the Peterson coil in
compensated networks or of the grounding resistor in grounded network as a result
the
Table 1222: Characteristic angle control for the RCA_CTL condition
Characteristic angle Setting
–90°
0°
REX640
Technical Manual
RCA = -90 deg
Max forward
Forward
angle
area
I
0
(operating quantity)
Min forward
angle
Min operate voltage
Characteristic angle should be set to a positive value if the operating
signal lags the polarizing quantity -VG or -VN, respectively, and a negative
value if operating signal leads the polarizing quantity, respectively.
Characteristic angle setting is adjusted to the operation according to the
Characteristic angle is set automatically to suit the earthing method.
-U ( polarizing quantity)
0
Min reverse angle
Max reverse angle
Min operate current
zero torque line
Characteristic angle recommended
0°
+60°
–90°
=FALSE
RCA_CTL
Characteristic angle = –90°
Characteristic angle = 0°
Protection related functions
Backward
area
Characteristic
Characteristic angle
Characteristic
=TRUE
RCA_CTL
Characteristic angle = 0°
Characteristic angle = –90°
1291