![background image](http://html1.mh-extra.com/html/abb/relion-670-series/relion-670-series_applications-manual_3052129234.webp)
The short circuit voltage can be calculated as:
0
1
0
0
1
0
1
1
1
1
(
)
3
3
3
3
m
m
ph
ph
E
Ep
ph
E
Ep
I
Z
Z
Z
Z
Z
Z
U
Z
I
I
Z I
I
I
Z
Z
=
-
-
×
+
×
+
×
=
+
×
+
×
IECEQUATION14006 V1 EN-US
(Equation 181)
Where I
Ep
is the ground current in the parallel line.
As explained above, the distance relay phase-to-earth measures:
ph
ph
N
E
Z
U
I
K
I
=
+
×
IECEQUATION14004 V1 EN-US
(Equation 182)
0
1
0
1
1
1
3
3
m
ph
E
Ep
ph
ph
n
E
ph
n
E
Z
Z
Z
Z
I
I
I
U
Z
Z
Z
I
K I
I
K I
=
-
+
×
+
×
=
×
+
×
+
×
IECEQUATION14007 V1 EN-US
(Equation 183)
Taking earth compensation factor
0
1
1
3
N
Z
Z
K
Z
-
=
for single circuit and
0
1
3
m
Nm
Z
K
Z
=
impedance
measured by distance relay can be written as:
1
1
Nm
Ep
ph
N
E
Z
Z
K
I
I
K
I
=
é
ù
×
+
ê
ú
+
×
ê
ú
ë
û
IECEQUATION14010 V1 EN-US
(Equation 184)
Where:
I
E
earth current of faulty line
I
EP
is earth current of the parallel line
Z
1
is line positive sequence impedance
K
N
is earth compensation factor for single circuit set at the relay
given by equation
Z
0m
is the zero sequence mutual coupling between the faulted and
the parallel line
0
1
1
3
N
Z
Z
K
Z
=
-
×
IECEQUATION14005 V1 EN-US
(Equation 185)
K
Z
Z
Nm
m
=
⋅
0
1
3
IEC13000297 V1 EN-US
(Equation 186)
Section 7
1MRK 505 343-UEN B
Impedance protection
228
Application manual
Содержание Relion 670 series
Страница 1: ...RELION 670 SERIES Line differential protection RED670 Version 2 1 IEC Application manual...
Страница 2: ......
Страница 40: ...34...
Страница 64: ...58...
Страница 150: ...144...
Страница 406: ...400...
Страница 472: ...466...
Страница 494: ...488...
Страница 512: ...506...
Страница 524: ...518...
Страница 604: ...598...
Страница 686: ...680...
Страница 718: ...712...
Страница 722: ...716...
Страница 758: ...752...
Страница 759: ...753...