ABB RER620 Technical Manual page 271

1MAC309294-MB F
RER620
Technical Manual
V2
VG
VN
I2
IG
IN
RCA_CTL
BLOCK
Figure 130: Functional module diagram
Directional detector
When "Neg. seq. volt." selection is made using Pol signal Sel, the directional detector
module compares angle of negative sequence current (I
(-V ). Using the negative sequence voltage angle as the reference the negative sequence
2
current angle is compared to the Characteristic angle. If the angle difference is within the
operating sector selected by Direction mode setting then enable signal is sent to the Timer.
The value of Characteristic angle should be chosen in such way that all the
faults in the operating direction are seen in the operating zone and all the
faults in the opposite direction are seen in the backward zone.
The operating sector is defined by the settings Max forward angle, Max reverse angle, Min
forward angle and Min reverse angle (see Figure 131). User selectable options for
Directional mode are "Forward" and "Reverse".
Timer
t
Directional
detector
Low level
blocking
Blocking
logic
) to the negative sequence voltage
2
Section 4
Protection functions
RELEASE
265