ABB REL 356 Current Differential Protection
3-27
Settings and Application
Figure 1. Ratio of I
3
F
min
/I
F
Gmin
vs. C0 (C1 = 0.1, C2 = 0.7)
Case 3
When the minimum ground fault current is less than 12.5% of minimum three phase fault current C0 should be set to 2.5.
The recommended settings
C1 = 0.1
C2 = 0.7
C0 = 2.5
gives the following sensitivity for different faults:
Three phase faults
Phase-phase faults
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
Single phase to ground faults
min
3
min
3
min
1
.
0
1
φ
φ
I
I
C
IT
⋅
−
=
⋅
−
=
min
min
min
0
.
1
)
0
2
1
(
3
1
G
G
I
I
C
C
C
IT
φ
φ
⋅
=
⋅
+
+
−
=
Summary of Contents for REL 356
Page 23: ...ABB REL 356 Current Differential Protection 1 10 Product Overview and Specifications ...
Page 83: ...ABB REL 356 Current Differential Protection 3 36 Settings and Application ...
Page 127: ...ABB REL 356 Current Differential Protection 5 28 Testing ...
Page 186: ...LINE SECTIONALIZING USING A PLC AND ABB PROTECTIVE RELAY Page 49 of 53 ...
Page 187: ...LINE SECTIONALIZING USING A PLC AND ABB PROTECTIVE RELAY Page 50 of 53 ...
Page 188: ...LINE SECTIONALIZING USING A PLC AND ABB PROTECTIVE RELAY Page 51 of 53 ...
Page 189: ...LINE SECTIONALIZING USING A PLC AND ABB PROTECTIVE RELAY Page 52 of 53 ...