ABB REL 356 Current Differential Protection
3-35
Settings and Application
Settings for OTH, C0, C1 and C2 for Tapped Load Applications
The relay setting OTH and the sequence filter constants, C1, C2 and C0, should be first selected according to normal
conditions following the recommendations. Then, the relay setting and the selected constants need to be checked to
make sure they satisfy the special requirements for tap load applications:
Following the procedure for the general case, the following settings were determined:
C1 = 0.1
C2 = 0.7
C0 = 0
OTH = 0.56 A
i.e. use criterion (2)
·
if
0
2
=
C
(1)
·
if
0
2
≠
C
(2)
where
LN
V
is the line-to-neutral voltage, in primary Volts
c
R
is the CT ratio,
Z is the total equivalent system impedance looking back into the system from the transformer bank, in high side ohms
T
Z
is the transformer impedance, in high side ohms
OTH
e
OTH
e
R
Z
Z
V
e
C
C
OTH
R
Z
V
e
C
C
j
j
C
T
LN
j
C
LN
j
<
=
⋅
⋅
=
⋅
⋅
+
⋅
⋅
+
⋅
>
=
⋅
⋅
=
⋅
⋅
⋅
⋅
+
⋅
⇒
⋅
+
⋅
⋅
+
⋅
>
>
⋅
⋅
⋅
+
⋅
°
°
−
−
46
.
0
34
.
2
66
.
0
3
.
0
3
240
)
65
.
66
08
.
4
(
2
138000
7
.
0
1
.
0
3
.
0
21
.
9
41
.
40
76
.
0
3
.
0
3
240
08
.
4
2
138000
7
.
0
1
.
0
3
.
0
2
3
.
0
2
3
.
0
120
60
120
2
1
60
2
1
ο
ο
Thus the settings established for the general case will be valid also for this tapped load application example.
C
T
LN
C
LN
R
Z
Z
V
C
OTH
R
Z
V
C
⋅
+
⋅
⋅
>
>
⋅
⋅
⋅
⋅
1
1
3
.
0
2
3
.
0
C
T
LN
j
C
LN
j
R
Z
Z
V
e
C
C
OTH
R
Z
V
e
C
C
⋅
+
⋅
⋅
+
⋅
>
>
⋅
⋅
⋅
+
⋅
−
2
3
.
0
2
3
.
0
120
2
1
60
2
1
ο
ο
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 ...
