ABB RELION REX640 Technical Manual page 357

1MRS759142 F
U
C
Figure 214: 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 397: Equations for calculating angle difference for positive-sequence quanti-
ty polarizing method
Faulted
phases
A
B
C
A - B
Table continues on the next page
REX640
Technical Manual
I
A
U
A
I
2
U U
CA AB
I
I
B
U
C
2
U
BC
A
Used Used
fault polarizi
current ng
voltage
I U
A 1
I U
B 1
I U
C 1
I -I U
A B 1
I
C
U
B
Angle difference
ANGLE A _ ( U ) (
ϕ ϕ
= −
1
ANGLE B _ ( U ) (
ϕ ϕ
= −
1
ANGLE C _ ( U ) (
= ϕ − ϕ
1
ANGLE A _ ( U ) (
= ϕ − ϕ
1
Protection functions
U
A
I
U
A
2
I
2
U U
C B
B
I )
ϕ
−
A RCA
o
I ) 120
ϕ
− −
B RCA
o
I ) 120
− ϕ +
RCA
C
o
I I ) 30
− − ϕ +
A B RCA
I
B
(Equation 22)
(Equation 23)
(Equation 24)
(Equation 25)
357