ABB Relion 650 Series Technical Manual page 451

1MRK 511 424-UEN B
Bay control REC650 2.2 IEC
Technical manual
F
A
Z pZ
I
A
A
U
A
IEC01000171 V1 EN-US
Figure 212: Fault on transmission line fed from both ends
From figure 212 it is evident that:
× × ×
U = I p Z + I R
A A L F F
EQUATION95 V1 EN-US
Where:
I is the line current after the fault, that is, pre-fault current plus current change due to the fault,
A
I is the fault current and
F
is a relative distance to the fault
p
The fault current is expressed in measurable quantities by:
I
F A
------- -
I
=
F
D
A
EQUATION96 V1 EN-US
Where:
I is the change in current at the point of measurement, IED A and
FA
D is a fault current-distribution factor, that is, the ratio between the fault current at line end A
A
and the total fault current.
For a single line, the value is equal to:
( ) Z ×
1 p – + Z
L B
-----------------------------------------
D =
A
Z + Z + Z
A L B
EQUATION97 V1 EN-US
Thus, the general fault location equation for a single line is:
L
(1-p).Z
I
L L
B
I
F
R
F
Section 10
Monitoring
B
Z
B
xx01000171.vsd
(Equation 24)
(Equation 25)
(Equation 26)
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