ABB RELION REF615R, Техническое руководство

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GUID-3318EF60-5E36-4872-B257-B44C54BC252F-ANSI V1 EN
Figure 200: Functional module diagram.
SCFD analysis
The self-clearing fault detection SCFD analysis module detects the self-clearing fault in
each phase by comparing the corresponding phase current magnitude to the set value
PhPu .
If the phase current I_A magnitude goes above double the set value PhPu , the module
calculates the time duration for which the current I_A continuously stays above double the
set value
PhPu . If the calculated time duration is greater than 1/4 cycles and less than the
number of cycles set by CyMulit , it regards that the self-clearing fault is observed in phase
A and
DetectfaultPhA
in the monitored data is set to "True". If the time duration
criterion fails,
PickUpNoTripA
in the monitored data is set to "True". Once the self-
clearing fault is detected in phase A, function increments the count
SCA
in the monitored
data, which keeps record of the number of times the fault has been detected.
Self-clearing faults in phase B and phase C are detected similarly as explained for phase
A, that is, by comparing I_B and I_C magnitudes to the set value
PhPu and by checking
the time duration. If the fault is detected in phase B or phase C,
DetectfaultPhB
or
respectively
DetectfaultPhC
in the monitored data is set to "True". If the time
duration criterion fails for phase B or phase C, the corresponding
PickUpNoTripB
or
PickUpNoTripC
in the monitored data is set to "True". Once the fault is detected in
phase B or phase C, the corresponding fault count
SCB
or
SCC
is incremented.
If the AdapPhPu setting is set to "True", the threshold setting value PhPu is adaptively
calculated for each phase separately. The adaptive threshold value set equal to the average
of the phase current over the 2
nd
and 3
rd
cycle after the AdapPhPu setting is set to "True".
Until the 3
rd
cycle, the set value PhPu is used for detecting the self-clearing fault. After the
3
rd
cycle, the adaptively calculated threshold value for each phase is used for detecting the
self-clearing fault.
This adaptive threshold implementation for each phase is considered only if the average
of the phase current over the 2
nd
and 3
rd
cycle is greater than setting AbsMinLoad .
Otherwise, the set value PhPu is considered for the corresponding phase fault detection.
1MRS240050-IB C
Section 6
Supervision functions
REF615R 379
Technical Manual