Schweitzer Engineering SEL-387-0, Instruction Manual

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5.19
Date Code 20170601 Instruction Manual SEL-387-0, -5, -6 Relay
Metering and Monitoring
Through-Fault Event Monitor
Figure 5.6 Distribution Feeder Faults Expose Transformer Bank to
Through Faults
Monitor and document this through-fault activity with the through-fault event
monitor in the SEL-387-5 and SEL-387-6 relays. The through-fault event
monitor captures maximum current levels, duration, and date/time for each
transformer through fault. The monitor also performs a simple I
2
t calculation
(analogous to the energy expended during the through fault) and cumulatively
stores calculation results for each monitored phase.
Through-Fault Event
Monitor Settings
Activate and adjust the through-fault event monitor with the settings in
Table 5.3 .
Setting ETHRU =N turns off the through-fault event monitor. Any other
setting selection for ETHRU designates the winding to monitor for through-
fault events. For example, ETHRU = 2 designates Winding 2 as the winding to
monitor for through-fault events. Specifically, Winding 2 current inputs
IAW2
,
IBW2
, and
ICW2
(A-phase, B-phase, and C-phase, respectively) are monitored
for maximum currents for through-fault events. Changing setting ETHRU
resets/clears through-fault event information (see
TFE C and TFE R
command discussions that follow).
Setting THRU triggers the through-fault event-the through-fault event monitor
starts acquiring maximum current and duration information, along with a date/
time tag. Typically, the THRU setting is set with an overcurrent element. For
example, set THRU to trigger a through-fault event on the pickup of a phase
instantaneous overcurrent element on Winding 2:
THRU = 50P23
To block triggering of through-fault events resulting from transformer inrush,
consider settings such as
THRU = 50P23 * !87BL
SEL-387
Through-Fault Current
Table 5.3 Through-Fault Event Monitor Settings
Setting Definition Range
ETHRU Enable Through-Fault Event Winding N, 1, 2, 3, 4
THRU Through-Fault Event Trigger
(SEL
OGIC
control equation)
Relay Word bits ( Table 4.9 )
ISQT Through-Fault I
2
t Alarm Threshold OFF,
0-4294967 (kA)
2
seconds
NOTE:
The above examples show the
designated current inputs
(ETHRU = 2) and triggering element
(THRU = 50P23) both from Winding 2.
While this is a common setting
approach, triggering elements can be
from any winding or be of any element
available in Table 4.9 (e.g.,
THRU = IN101; set to trigger a through-
fault event on the assertion of input
IN101 ).