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Trigger signal for data recording
Figure 2.32-3 shows a trigger signal for data recording. If elements operate and switches are
closed, the FL records the data of current and voltage. It is also possible that the FL starts to
record these data when the PLC
1
signal is appeared.
Figure 2.32-3 Data recording trigger from the DIFL and the PLC
1
Note: User can configure a signal with the PLC logic. For more information on the PLC,
see Chapter
PLC function
.
2
Note: Respective switches in the above figure are closed when respective elements
operate. After that, data recording is provided for the FL. Elements and
characteristics (DIFL, RDIF, DIFG, and RDIFG) are discussed in the DIFL. See
Chapter
Relay application: Segregated current differential protection
.
Trigger signal for FL calculation
Figure 2.32-4 shows a calculation trigger; the calculation is carried out when the FL receives
the result signals of the DIFL and the DIFG. The calculation also starts by the PLC signal.
Figure 2.32-4 Calculation trigger from the DIF function and PLC
(iii) Calculation error
User should note that the calculation error might be larger when a setting value is far from
the actual data of line impedance. For example, if abnormal settings
1
are done, the calculation
error will be appeared notably.
1
Note: Abnormal settings can be exist when values are far from actual impedance data of
transmission line. For example, resistance value is so larger then reactance value,
Operation signal from DIFL
2
element
Operation signal from RDIF
2
element
Operation signal from DIFG
2
element
Operation signal from RDIFG
2
element
Trigger signal for data recording:
Current and voltage data are saved
by the operation signals from
elements.
Trigger signal for calculation:
Calculation of fault locator is
initiated by the DIFL or the DIFG.
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