Date Code 20000421
Maintenance and Testing
7-23
SEL-251, -2, -3 Instruction Manual
reverts back to shot = 0, and the A4 output contact deasserts (A4 =
79SH
).
or
Current is reapplied to the relay and trips the circuit breaker simulator
again before the reset interval timer expires. The shot counter is incre-
mented to shot = 2 and the A4 output contact deasserts (A4 =
79SH
).
The A2 output contact remains asserted (A2 =
79CY
).
If you follow
Reclosing Relay Open Interval Timer Test
steps 6 through 8, the
relay trips again before the reset interval expires. The shot counter is then
incremented to the next shot.
5. If you repeat these steps, the reclosing relay shot counter will increment until
shot = 3. Because of the M79SH setting (M79SH = 01010), the A4 output
contact will assert again for shot = 3 (A4 =
79SH
).
The reclosing relay will go to lockout on the next trip because shot = 3 is the last
shot. The front panel LO (lockout) LED illuminates, the A3 output contact
asserts (A3 =
79LO
) and the A2 output contact deasserts (A2 =
79CY
). The
shot counter remains at shot = 3 (last shot) and the A4 output contact remains
asserted (A4 =
79SH
).
Reclosing Relay Sequence Coordination Test
Purpose:
Verify the operation of the reclosing relay sequence coordination feature.
Method:
1. Enter the settings in
Reclosing Relay Tests Setup
if you haven't already. Make
the following changes to these settings:
.
.
.
TR(1246)
= NA
no programmable trip conditions
.
.
.
SEQ(1)
= 50L
sequence coordination control condition
The
79SH
Relay Word bit monitors any desired state of the shot counter. In this
example, it is assigned to the A4 output contact (A4 =
79SH
).
This test does not require an external timer.
2. Execute the CLOSE command or energize the IN4 input (IN4 = DC; direct close)
to cause CLOSE output contact assertion. With the circuit breaker simulator
closed, IN5 is energized (IN5 = 52A) and the front panel RS (reset) LED
illuminates after the reset interval timer expires (79RST = 1800 cycles). The A1
output contact asserts (A1 =
79RS
) and shot = 0.