ABB Relion REC615 - Page 248

U
A
U
B
U
C
U
BC
U
AB
U
CA
I
A
I
B
I
C
U
2
I
2
U
A
U
B
U
C
I
A
I
B
I
C
U
2
I
2
A
B
Figure 128: Phasors in a single-phase earth fault, phases A-N, and two-phase short
circuit, phases B and C, when the actuating polarizing quantity is the negative-
sequence voltage -U2
Positive sequence voltage as polarizing quantity
Table 262: Equations for calculating angle difference for positive-sequence quanti-
ty polarizing method
Faulted
phases
Used
fault
current
Used
polarizing
voltage
Angle difference
A I
A
U
1
ANGLE A U I
A
RCA
_ ( ) ( )= − − ϕ ϕ ϕ
1
B I
B
U
1
ANGLE B U I
B
RCA
_ ( ) ( )= − − − ϕ ϕ ϕ
1
120
o
C I
C
U
1
ANGLE C U I
C
RCA
_ ( ) ( )= − − + ϕ ϕ ϕ
1
120
o
A - B I
A
- I
B
U
1
ANGLE A U I I
A B
RCA
_ ( ) ( )= − − − + ϕ ϕ ϕ
1
30
o
B - C I
B
- I
C
U
1
ANGLE B U I I
B C
RCA
_ ( ) ( )= − − − − ϕ ϕ ϕ
1
90
o
C - A I
C
- I
A
U
1
ANGLE C U I I
C A
RCA
_ ( ) ( )= − − − + ϕ ϕ ϕ
1
150
o
Protection functions 1MRS758755 C
248 REC615 & RER615
Technical Manual