7. Close S2 and adjust the test current to the appropri-
ate value shown in Column B of Table 9.
8. Release S2 to simulate a backup opening. The sec-
tionalizer should count the overcurrent interruption and
open.
9. Repeat steps 3 through 7 for phases B and C.
10. Remove the jumper from terminals P and D.
11. Remove the jumper from across the ground actuating cur-
rent resistor upon completion of this portion of the test.
Ground Minimum Actuating Current
To prevent the possibility of a false count, the phase sensing por-
tion of the sectionalizer control circuit should be disabled when
the ground minimum actuating current is being checked.
The following procedure should be used:
1. Jumper the phase actuating current resistor with a
short lead to disable the phase sensing circuit.
2. Jumper terminals P and D together.
3. Check that the sectionalizer control is set for one-
count-to-open.
4. Close the sectionalizer by operating the Manual
Control Switch to “CLOSE”.
5. With the test circuit connected to phase A of the sec-
tionalizer and S1 open, hold S2 closed and slowly raise
the test current from zero to the appropriate value
shown in Column A of Table 9. Hold S2 closed at this
current for at least three seconds.
6. Release S2 and simulate a backup opening. The
sectionalizer should not open.
7. Close S2 and adjust the test current to the appropriate
value shown in Column B of Table 9.
8. Release S2 to simulate a backup opening. The sectional-
izer should count the overcurrent interruption and open.
9. Repeat steps 3 through 7 for Phases B and C.
10. Remove the jumper from terminals P and D.
10. Remove the jumper from across the phase actuat-
ing current resistor.
Count Restraint
The count restraint feature prevents erroneous counts
of overcurrents interrupted by downline protective
devices by blocking the counting operation as long as
a minimum of 0.5 amps of uninterrupted line current
flows through the sectionalizer.
The operation of the count restraint can be verified by
superimposing an interruptible overcurrent on a constant
minimum line current. The sectionalizer will not count or
open on the interruption of the overcurrent as long as
the minimum line current is not interrupted. To check the
ground restraint feature, proceed as follows:
1. Jumper the ground actuating current resistor with a
short lead to disable the phase sensing circuit.
2. Jumper terminals P and D together.
3. Check that the sectionalizer control is set for one-
count-to-open.
4. Close the sectionalizer by operating the Manual
Control Switch to “CLOSE”.
5. With the test circuit connected to phase A of the
sectionalizer and S1 open, hold S2 closed (to simu-
late a constant load current of approximately 6
amps), hold S2 closed and raise the test current
slightly above the appropriate value shown in
Column B of Table 9. Hold S2 closed at this current
for at least three seconds.
6. Release S2 and simulate a downline device clearing
the overcurrent. The sectionalizer should not open,
verifying the operation of the count restraint feature.
7. Open S1 and again close and adjust S2 to simulate a
backup device clearing the fault. This time the sectional-
izer should count the overcurrent interruption and open.
8. Remove the jumper from terminals P and D.
17
S280-21-1
Table 9
Test Circuit Operating Limits for Actuating Current
Settings
Column A
Column B
Actuating
Sectionalizer Must Sectionalizer Must
Current Setting
Not Count Below
Count At
(amps)
(amps)
(amps)
3.5
3
4
7
6.3
7.7
16
14.4
17.6
20
18
22
24
21.6
26.4
28
25.2
30.8
40
36
44
56
50.4
61.6
80
72
88
112
101
124
160
144
176
224
201
247
256
230
282
296
266
326
320
288
352
448
403
483
480
432
528
640
576
704