ABB REL650 Applications Manual page 454

Section 14
Monitoring
448
The Fault locator algorithm uses phase voltages, phase currents and residual current in
observed bay (protected line) and residual current from a parallel bay (line, which is
mutual coupled to protected line).
The Fault locator has close connection to the Disturbance report function. All external
analog inputs (channel 1-30), connected to the Disturbance report function, are available
to the Fault locator and the function uses information calculated by the Trip value
recorder. After allocation of analog inputs to the Disturbance report function, the user has
to point out which analog inputs to be used by the Fault locator. According to the default
settings the first four analog inputs are currents and next three are voltages in the observed
bay (no parallel line expected since chosen input is set to zero). Use the Parameter Setting
tool within PCM600 for changing analog configuration.
The list of parameters explains the meaning of the abbreviations. Figure
these system parameters graphically. Note, that all impedance values relate to their
primary values and to the total length of the protected line.
R +jX
1A 1A
DRPRDRE
LMBRFLO
ANSI05000045 V2 EN
Figure 211: 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 , R ) and analog input are set at zero.
0M 0M
Power system specific parameter settings shown in table 2 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.
R +jX
0L 0L
R +jX
1L 1L
Z =Z +jX
0m 0m 0m
R +jX
0L 0L
R +jX
1L 1L
ANSI05000045_2_en.vsd
1MRK 506 334-UUS A
211 also presents
R +jX
1B 1B
Application manual