ABB RER620 Technical Manual page 266

Section 4
Protection functions
260
V1
I1
BLOCK
Figure 127: Functional module diagram
Directional detector
The Directional detector module compares the angle of positive sequence current (I
the angle of positive sequence voltage (V
the reference the positive sequence current angle is compared to the Characteristic angle
setting. If the angular difference is within the operating sector selected by the Directional
mode setting, then enable signal is sent to the Timer.
The operating sector is defined by the setting Min forward angle, Max forward angle, Min
reverse angle, and Max reverse angle (see Figure 128). The user selectable options for
Directional mode settings are "Forward" and "Reverse"
The sector limits are always given as positive degree values.
The Characteristic angle is also known as Relay Characteristic Angle
(RCA), Relay Base Angle or Maximum Torque Line.
Timer
Directional
t
detector
Low level
blocking
Blocking
logic
). Using the positive sequence voltage angle as
1
1MAC309294-MB F
RELEASE
) to
1
RER620
Technical Manual