Siemens SIPROTEC 7SJ62 Instruction Manual page 187

Table 6-2 Voltage and Current Values for the Determination of Fault Direction
Pick up Current
A Ia
B
C
G
A, G Ia
B, G
C, G
A, B Ia
B, C
C, A Ia
A, B, G Ia
B, C, G
C, A, G Ia
A, B, C Ia
A, B, C, G Ia
7SJ62 Manual
C53000-G1140-C121-1
V
A
V
C
V
B C
a) Phase to Ground Fault (a-g)
Figure 6-23 Voltages Used for Direction Determination
Table 6-2 shows the assignment of voltage and current values for the determination of fault di-
rection for various types of short-circuit faults.
A
Voltage Current
V
bc
I
b
V
bc
I
b
V I
bc b
I
b
V
bc
V I
bc b
I
b
V
bc
V I
bc b
V I
bc b
1
) or 3 * V = V + V + V
0 ag bg
The direction curve for the directional phase relay element is shown in Figure 6-24 in
a complex R-X diagram. The curve illustrates the operating direction of the relay in
terms of the impedance viewed by the directional phase relay element, that is, the ratio
of the directional phase element polarizing voltage to the directional phase element
current. Line 'a' represents the directional limit line, and when the protective relay
V
B
B
Voltage Current
V
ca
I
c
V
ca
I
c
V
ca
V I
ca c
I
c
V
ca
V I
ca c
I
c
V I
ca c
V I
ca c
, depending on type of connection for the voltages
cg
V
A
V
A B
V
C A
V
V
C
V
B C
b) Phase to Phase Fault (a-c)
C GROUND
Voltage Current
V
ab
I
0
I
0
I
0
V I
ab 0
V
ab
V
ab
I
0
V I
ab 0
V I
ab 0
V
ab
V I
ab 0
Functions
B
Voltage
1
V )
0
1
V )
0
1
V )
0
1
V )
0
1
V )
0
1
V )
0
1
V )
0
1
V )
0
6-47