Instruction manual
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AQ G3x7 Generator protection IED
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Table 3-46: Output signals of the characteristics logic.
3.2.21.5
The phase selection logic and timing
In case of faults, the calculated impedance value for the faulty loop is inside a polygon. If
the fault is near the relay location, the impedances in the loop containing the faulty phase
can also be inside the polygon. To ensure selective tripping, phase selection is needed.
This chapter explains the operation of the phase selection logic.
Table 3-47: Inputs needed to decide start of impedance protection
Table 3-48: Binary output signals of the phase selection