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Measured Value
Correction for
Parallel Lines
(optional)
7SA6 Manual
C53000-G1176-C156-2
Table 6-8 lists all measured values used for the distance measuring in isolated or res-
onant-earthed systems.
Table 6-8
Evaluation of measured loops for a multiple pick-up in non-earthed systems
Fault detection
Loops
L1–E, L2–E, (L1–L2)
L2–E, L3–E, (L2–L3)
L1–E, L3–E, (L3–L1)
L1–E, L2–E, (L1–L2)
L2–E, L3–E, (L2–L3)
L1–E, L3–E, (L3–L1)
L1–E, L2–E, (L1–L2)
L2–E, L3–E, (L2–L3)
L1–E, L3–E, (L3–L1)
L1–E, L2–E, (L1–L2)
L2–E, L3–E, (L2–L3)
L1–E, L3–E, (L3–L1)
L1–E, L2–E, (L1–L2)
L2–E, L3–E, (L2–L3)
L1–E, L3–E, (L3–L1)
L1–E, L2–E, (L1–L2)
L2–E, L3–E, (L2–L3)
L1–E, L3–E, (L3–L1)
L1–E, L2–E, (L1–L2)
L2–E, L3–E, (L2–L3)
L1–E, L3–E, (L3–L1)
L1–E, L2–E, (L1–L2)
L2–E, L3–E, (L2–L3)
L1–E, L3–E, (L3–L1)
L1–E, L2–E, (L1–L2)
L2–E, L3–E, (L2–L3)
L1–E, L3–E, (L3–L1)
During earth faults on parallel lines, the impedance values calculated by means of the
loop equations are influenced by the coupling of the earth impedance of the two con-
ductor systems (Figure 6-27). Unless special measures are employed, this results in
measuring errors in the result of the impedance computation. A parallel line compen-
sation may therefore be activated. In this manner the earth current of the parallel line
is taken into consideration by the line equation and thereby allows for compensation
of the coupling influence. The earth current of the parallel line must be connected to
the device for this purpose. The loop equation is then modified as shown below, refer
also to Figure 6-24
⋅
⋅
Z
Z
I
–
I
–
I
L3
L
E
E
EP
Z
⋅
⋅
⋅
Z
Z
------ - I
I
–
I
L3
L
E
L
Z
where I
is the earth current of the parallel line and the ratio Z
EP
parameter, resulting from the geometry of the double circuit line and the nature of the
Evaluated
Loop(s)
L1–E
L3–E
L3–E
L1–E
L3–E
L1–E
L2–E
L2–E
L1–E
L1–E
L2–E
L1–E
L2–E
L3–E
L3–E
L2–E
L2–E
L3–E
L1–E
L2–E
L3–E
L2–E
L3–E
L1–E
L1–E, L2–E
L2–E, L3–E
L3–E, L1–E
⋅
Z
U
=
M
L3–E
Z
E
M
⋅
⋅
Z
-------
U
–
=
EP
L
L3–E
Z
L
L
Functions
Setting
Parameter 1221
PHASE PREF.2phe =
L3 (L1) acyclic
PHASE PREF.2phe =
L1 (L3) acyclic
PHASE PREF.2phe =
L2 (L1) acyclic
PHASE PREF.2phe =
L1 (L2) acyclic
PHASE PREF.2phe =
L3 (L2) acyclic
PHASE PREF.2phe =
L2 (L3) acyclic
PHASE PREF.2phe =
L3 (L1) cyclic
PHASE PREF.2phe =
L1 (L3) cyclic
PHASE PREF.2phe =
All loops
/Z
is a constant line
M
L
6-47
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