Schweitzer Engineering SEL-351P - Additional Example; Factory Default Setting Example

Date Code 990430 Breaker/Recloser Monitor, Battery System Monitor, 8-13
Metering, and Load Profile Functions
SEL-351P Manual Técnico
the decision has to be made: where is this current and trip count information accumulated? Is it
under recloser control initiated trips
or externally initiated trips?
To make this determination, the status of the TRIP Relay Word bit is checked at the instant
BKMON asserts (TRIP is the logic output of Figure 5.1). If TRIP is asserted (TRIP = logical 1),
the current and trip count information is accumulated under recloser control initiated trips
(Cntrl
Trips). If TRIP is deasserted (TRIP = logical 0), the current and trip count information is
accumulated under externally initiated trips
(Ext Trips).
Regardless of whether the current and trip count information is accumulated under control
initiated trips or externally initiated trips, this same information is routed to the breaker
maintenance curve for continued breaker wear integration (see
Figure SECTION 8: .3 through
Figure SECTION 8: .7).
Factory Default Setting Example
Previously as discussed, the SEL
OGIC Control Equation breaker monitor initiation factory default
setting is:
BKMON = WBTR + WBTRT + \52A
Thus, any new assertion of WBTR is classified as a recloser control trip (TRIP is asserted at the
same time), and the current and trip count information is accumulated under recloser control
initiated trips (Cntrl Trip).
Refer to Figure 7.29. Relay Word bit WBTRT asserts ¼ cycle after WBTR (trip output) asserts.
WBTRT remains asserted for an additional 30 cycles after WBTR (trip output) deasserts. This
30-cycle dropout time overlaps any operation of the 52a auxiliary contact (52A = WB52A). The
momentary assertion of \52A (falling-edge detection of 52A) is not noticed by the BKMON
setting when the control issues a trip – it is already asserted to logical 1 by WBTRT.
Any momentary assertion of \52A (falling edge of 52A), without the overlap of WBTRT, is
indicative of the recloser being opened manually (i.e., opened via the external manual
trip/lockout lever) and is classified as an external trip and the trip count information is
accumulated under externally initiated trips
(Ext Trips). 52A status lags the main contacts by
over a cycle, so it is doubtful that any current information will be accumulated for a manual trip
(would be load current anyway).
Additional Example
Refer to
Figure SECTION 8: .8. Output contact OUT101 is set to provide tripping:
OUT101 = TRIP
Note that optoisolated input IN102 monitors the trip bus. If the trip bus is energized by output
contact OUT101, an external control switch, or some other external trip, then IN102 is asserted.