ABB RELION REX640 Technical Manual page 353

1MRS759142 F
In an example case of the phasors in a single-phase earth fault where the faulted
phase is phase A, the angle difference between the polarizing quantity U
operating quantity I
need to rotate the polarizing quantity.
Figure 210: Single-phase earth fault, phase A
In an example case of a two-phase short-circuit failure where the fault is between
phases B and C, the angle difference is measured between the polarizing quantity U
and operating quantity I
BC
Figure 211: Two-phase short circuit, short circuit is between phases B and C
REX640
Technical Manual
is marked as φ. In the self-polarization method, there is no
A
- I in the self-polarizing method.
B C
Protection functions
and
A
353