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2 Functions
Parallel Line Mea-
sured Value Correc-
tion (optional)
70
Table 2-3
Evaluation of the Measuring Loops for Multi-phase Pickup in the Non-earthed
Network
Loop pickup
L1-E, L2-E, (L1-L2)
L1-E
L2-E, L3-E, (L2-L3)
L3-E
L1-E, L3-E, (L3-L1)
L3-E
L1-E, L2-E, (L1-L2)
L1-E
L2-E, L3-E, (L2-L3)
L3-E
L1-E, L3-E, (L3-L1)
L1-E
L1-E, L2-E, (L1-L2)
L2-E
L2-E, L3-E, (L2-L3)
L2-E
L1-E, L3-E, (L3-L1)
L1-E
L1-E, L2-E, (L1-L2)
L1-E
L2-E, L3-E, (L2-L3)
L2-E
L1-E, L3-E, (L3-L1)
L1-E
L1-E, L2-E, (L1-L2)
L2-E
L2-E, L3-E, (L2-L3)
L3-E
L1-E, L3-E, (L3-L1)
L3-E
L1-E, L2-E, (L1-L2)
L2-E
L2-E, L3-E, (L2-L3)
L2-E
L1-E, L3-E, (L3-L1)
L3-E
L1-E, L2-E, (L1-L2)
L1-E
L2-E, L3-E, (L2-L3)
L2-E
L1-E, L3-E, (L3-L1)
L3-E
L1-E, L2-E, (L1-L2)
L2-E
L2-E, L3-E, (L2-L3)
L3-E
L1-E, L3-E, (L3-L1)
L1-E
L1-E, L2-E, (L1-L2)
L1-E, L2-E
L2-E, L3-E, (L2-L3)
L2-E, L3-E
L1-E, L3-E, (L3-L1)
L3-E; L1-E
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 2-16). This causes measuring errors in the result of the imped-
ance computation unless special measures are taken. A parallel line compensation
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 2-13.
I
· Z
– I
· Z
– I
· Z
L3
L
E
E
EP
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
ground below the line. These line parameters are input to the device — along with all
Evaluated loop(s)
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
= U
M
L3-E
Setting of parameter 1220
/Z
is a constant line
M
L
7SA522 Manual
C53000-G1176-C155-3
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