ABB RELION REX640 - Page 354

Cross-polarizing as polarizing quantity
Table 396: Equations for calculating angle difference for cross-polarizing method
Faulted
phases
Used
fault
current
Used
polarizi
ng
voltage
Angle difference
A I
A
U
BC
ANGLE A U I
BC
A
RCA
o
_ ( ) - ( ) - = + ϕ ϕ ϕ 90
(Equation 15)
B I
B
U
CA
ANGLE B U I
CA
B
RCA
o
_ ( ) - ( ) - = + ϕ ϕ ϕ 90
(Equation 16)
C I
C
U
AB
ANGLE C U I
AB
C
RCA
o
_ ( ) - ( ) - = + ϕ ϕ ϕ 90
(Equation 17)
A - B I
A
-I
B
U
BC
-U
CA
ANGLE A U U I I
BC CA
A B
RCA
o
_ ( - ) - ( - ) - = + ϕ ϕ ϕ 90
(Equation 18)
B - C I
B
-I
C
U
CA
-U
AB
ANGLE B U U I I
CA AB
B C
RCA
o
_ ( - ) - ( - ) - = + ϕ ϕ ϕ 90
(Equation 19)
C - A I
C
-I
A
U
AB
-U
BC
ANGLE C U U I I
AB BC
C A
RCA
o
_ ( - ) - ( - ) - = + ϕ ϕ ϕ 90
(Equation 20)
The angle difference between the polarizing quantity U
BC
and operating quantity I
A
is marked as φ in an example of the phasors in a single-phase earth fault where
the faulted phase is phase A. The polarizing quantity is rotated with 90 degrees. The
characteristic angle is assumed to be ~ 0 degrees.
Protection functions
1MRS759142 F
354 REX640
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