ABB REL 356 Current Differential Protection
3-26
Settings and Application
The recommended settings
C1 = 0.1
C2 = 0.7
C0 = 0.0
gives the following sensitivity for different faults:
Three phase faults
Phase-phase faults
Single phase to ground faults
Case 2
When the minimum ground fault current is substantially smaller than the minimum three phase fault current, C0 can be
given a value to increase the sensitivity for ground fault.
The recommended settings
C1 = 0.1
C2 = 0.7
C0 = according to Figure 1
gives the following sensitivity for different faults:
Three phase faults
Phase-phase faults
Single phase to ground faults
The value of C0 is determined from Figure 1. Calculate the ratio I
3
F
min
/I
F
Gmin
and find this number on the vertical axis.
Find the C0 for the calculated current ratio based on the curve corresponding to the least sensitive fault type.
Selecting C0 is this way results in the same sensitivity for minimum ground fault current as for minimum three phase
fault current.
min
3
min
3
min
1
.
0
1
φ
φ
I
I
C
IT
⋅
−
=
⋅
−
=
min
3
min
3
min
min
60
min
33
.
0
2
3
38
.
0
38
.
0
)
2
1
(
3
1
φ
φ
φφ
φφ
I
I
I
I
e
C
C
IT
j
⋅
=
⋅
⋅
=
⋅
=
⋅
⋅
+
−
=
±
ο
min
min
min
2
.
0
)
0
2
1
(
3
1
G
G
I
I
C
C
C
IT
φ
φ
⋅
=
⋅
+
+
−
=
min
3
min
3
min
1
.
0
1
φ
φ
I
I
C
IT
⋅
−
=
⋅
−
=
min
3
min
3
min
min
60
min
33
.
0
2
3
38
.
0
38
.
0
)
2
1
(
3
1
φ
φ
φφ
φφ
I
I
I
I
e
C
C
IT
j
⋅
=
⋅
⋅
=
⋅
=
⋅
⋅
+
−
=
±
ο
Содержание REL 356
Страница 23: ...ABB REL 356 Current Differential Protection 1 10 Product Overview and Specifications ...
Страница 83: ...ABB REL 356 Current Differential Protection 3 36 Settings and Application ...
Страница 127: ...ABB REL 356 Current Differential Protection 5 28 Testing ...
Страница 186: ...LINE SECTIONALIZING USING A PLC AND ABB PROTECTIVE RELAY Page 49 of 53 ...
Страница 187: ...LINE SECTIONALIZING USING A PLC AND ABB PROTECTIVE RELAY Page 50 of 53 ...
Страница 188: ...LINE SECTIONALIZING USING A PLC AND ABB PROTECTIVE RELAY Page 51 of 53 ...
Страница 189: ...LINE SECTIONALIZING USING A PLC AND ABB PROTECTIVE RELAY Page 52 of 53 ...