Figure 149: Functional module diagram
Directional calculation
The directional calculation compares the current phasors to the polarizing phasor.
A suitable polarization quantity can be selected from the different polarization
quantities, which are the positive-sequence voltage, negative-sequence voltage,
self-polarizing (faulted) voltage and cross-polarizing voltages (healthy voltages).
The polarizing method is defined with the
Pol quantity
setting.
Table 293: Polarizing quantities
Polarizing quantity Description
Pos. seq. volt Positive sequence voltage
Neg. seq. volt Negative sequence voltage
Self pol Self polarization
Cross pol Cross polarization
The directional operation can be selected with the
Directional mode
setting.
The user can select either "Non-directional", "Forward" or "Reverse" operation. By
setting the value of
Allow Non Dir
to "True", the non-directional operation is allowed
when the directional information is invalid.
The
Characteristic angle
setting is used to turn the directional characteristic. The
value of
Characteristic angle
should be chosen in such a way that all the faults
in the operating direction are seen in the operating zone and all the faults in the
Protection functions
1MRS757644 H
300 620 series
Technical Manual
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