Z
0m
=Z
0m
+jX
0m
R
1A
+jX
1A
R
0L
+jX
0L
R
1L
+jX
1L
R
0L
+jX
0L
R
1L
+jX
1L
R
1B
+jX
1B
DRPRDRE
LMBRFLO
ANSI05000045_2_en.vsd
ANSI05000045 V2 EN
Figure 398: Simplified network configuration with network data, required for settings
of the fault location-measuring function
For a single-circuit line (no parallel line), the figures for mutual zero-sequence impedance
(X
0M
, R
0M
) and analog input are set at zero.
Power system specific parameter settings are not general settings but specific setting
included in the setting groups, that is, this makes it possible to change conditions for the
Fault locator with short notice by changing setting group.
The source impedance is not constant in the network. However, this has a minor influence
on the accuracy of the distance-to-fault calculation, because only the phase angle of the
distribution factor has an influence on the accuracy. The phase angle of the distribution
factor is normally very low and practically constant, because the positive sequence line
impedance, which has an angle close to 90°, dominates it. Always set the source
impedance resistance to values other than zero. If the actual values are not known, the
values that correspond to the source impedance characteristic angle of 85° give
satisfactory results.
18.8.3.1 Connection of analog currents
Connection diagram for analog currents included IN from parallel line shown in figure
399.
1MRK 506 369-UUS - Section 18
Monitoring
Line distance protection REL670 2.2 ANSI 847
Application manual
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