ABB RELION REX640 Technical Manual page 1283

Protection and control

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1MRS759142 F

Figure 727: Functional module diagram

Directional detector

The Directional detector module compares the angle of the positive-sequence

current I1 to the angle of the positive-sequence voltage V1. Using the positive-

sequence voltage angle as reference, the positive-sequence current angle is

compared to the

operating sector selected with the

The operating sector is defined by the setting

angle , Min reverse angle and Max reverse angle . The options that can be selected for

Low-level blocking

For a reliable operation, signal levels should be greater than the minimum level.

If they are not greater than the minimum level, Timer is blocked. If the amplitude

of the positive-sequence current is greater than the

positive-sequence voltage amplitude is greater than the

On signal is sent to Timer.

Once activated, the internal operating timer is started. The Timer characteristic is

according to definite time DT. When Timer has reached the value of

time , the RELEASE output is activated. If a drop-off situation happens, that is, if

the operating current moves outside the operating sector or signal amplitudes drop

Technical Manual

Characteristic angle setting. If the angular difference is within the

Directional mode setting are "Forward" and "Reverse".

The sector limits are always given as positive degree values.

Characteristic angle setting is also known as Relay Characteristic

Angle (RCA), Relay Base Angle or Maximum Torque Line.

Directional mode setting, the On signal is sent to

Min forward angle , Max forward

Protection related functions

Min trip current value and the

Min trip voltage value, the

Release delay