D
A
1 p–( ) Z
A
Z
AL
Z
B
+ +( ) Z
B
+×
2 Z
A
Z
L
2 Z
B
×+ +×
-----------------------------------------------------------------------------
=
EQUATION101 V1 EN-US (Equation 84)
The K
N
compensation factor for the double line becomes:
K
N
Z
0L
Z
1L
–
3 Z
1L
×
------------------------
Z
0M
3 Z
1L
×
-----------------
I
0P
I
0A
-------
×+=
EQUATION102 V1 EN-US (Equation 85)
From these equations it can be seen, that, if Z
0m
= 0, then the general fault location
equation for a single line is obtained. Only the distribution factor differs in these
two cases.
Because the D
A
distribution factor according to equation
81 or 83 is a function of
p, the general equation 83 can be written in the form:
EQUATION103 V1 EN-US (Equation 86)
Where:
K
1
U
A
I
A
Z
L
×
----------------
Z
B
Z
L
Z
A DD
+
---------------------------
1+ +=
EQUATION104 V1 EN-US (Equation 87)
K
2
U
A
I
A
Z
L
×
----------------
Z
B
Z
L
Z
A DD
+
---------------------------
1+
è ø
æ ö
×=
EQUATION105 V1 EN-US (Equation 88)
K
3
I
FA
I
A
Z
L
×
----------------
Z
A
Z
B
+
Z
1
Z
A DD
+
---------------------------
1+
è ø
æ ö
×=
EQUATION106 V1 EN-US (Equation 89)
and:
• Z
ADD
= Z
A
+ Z
B
for parallel lines.
• I
A
, I
FA
and U
A
are given in the above table.
• K
N
is calculated automatically according to equation
85.
• Z
A
, Z
B
, Z
L
, Z
0L
and Z
0M
are setting parameters.
For a single line, Z
0M
= 0 and Z
ADD
= 0. Thus, equation 86 applies to both single
and parallel lines.
Equation
86 can be divided into real and imaginary parts:
1MRK 505 394-UEN A Section 15
Monitoring
Line differential protection RED650 2.2 IEC 597
Technical manual
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