ABB Relion 620 Series, Technical Manual

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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 158: 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 299: Equations for calculating angle difference for positive-sequence quan-
tity 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
1MRS757644 H Protection functions
620 series
Technical Manual
313