ABB 615 Series ANSI, Technical Manual

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1MAC050144-MB C
Section 4
Protection functions
615 series ANSI 281
Technical Manual
Figure 132: Functional module diagram
Directional detector
The Directional detector module compares the angle of positive sequence current (I
1
) to
the angle of positive sequence voltage (V
1
). Using the positive sequence voltage angle as
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 133). 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.
Directional
detector
V1
I1
BLOCK
RELEASE
Blocking
logic
t
Timer
Low level
blocking