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Fault locator (FLOC)
and:
•
Z
= Z
+ Z
for parallel lines.
ADD
A
B
•
I
, I
and U
are given in the above table.
A
FA
A
•
KN is calculated automatically according to equation 67.
•
Z
, Z
, Z
, Z
and Z
A
B
L
0L
Equation 70 can be divided into real and imaginary parts:
2
⋅
(
)
(
) R
p
p Re K
Re K
–
+
1
2
⋅
⋅
(
)
⋅
(
) R
p Im
K
Im
K
–
+
–
1
2
If the imaginary part of K
then inserted to equation 74. According to equation 74, the relative distance to the fault
is solved as the root of a quadratic equation.
Equation 74 gives two different values for the relative distance to the fault as a solution.
A simplified load compensated algorithm, that gives an unequivocal figure for the rel-
ative distance to the fault, is used to establish the value that should be selected.
If the load compensated algorithms according to the above do not give a reliable solu-
tion, a less accurate, non-compensated impedance model is used to calculate the relative
distance to the fault.
7KH QRQFRPSHQVDWHG LPSHGDQFH PRGHO
In the non-compensated impedance model, I
current:
⋅
⋅
⋅
U
p Z
I
R
I
=
+
A
1 L
A
F
A
Where:
I
is according to table 15.
A
are setting parameters.
0M
⋅
(
)
Re K
0
–
=
F
3
⋅
⋅
(
)
Im
K
0
=
F
3
is not zero, R
can be solved according to equation 75, and
3
F
line current is used instead of I
A
&KDSWHU
0RQLWRULQJ
(Equation 74)
(Equation 75)
fault
FA
(Equation 76)
333
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