RESIDUAL OVERCURRENT ELEMENT TESTS
Verify the pickup thresholds of the 67N and 51NP residual overcurrent ele-
ments.
Using the LOGIC command, set the desired programmable output (A1 - A4) to
follow the appropriate overcurrent element. Select one of the overcurrent
elements from the Relay Word as indicated below:
67N
= Instantaneous Residual Element (pickup set by 67NP setting)
51NP
= Residual Time-Overcurrent Pickup Element
Disable all directional and LOP functions for this test. Set 5lNTC, 67NTC,
and LOPE = N.
Apply current to one phase and observe the pickup and dropout of each ele-
ment. Record the results.
Purpose:
Method: 1.
2 .
3 .
RESIDUAL TIME-OVERCURRENT ELEMENT TIMING TESTS
Purpose:
Verify the 51NT residual time-overcurrent element operating time.
Method: 1.
Disable all directional functions for this test. Set 51NTC and LOPE = N.
2.
Set a programmable output (A1 - A4) to follow the 51NP time-overcurrent
pickup element. Use the assertion of this output (open to close) to start an
external timer.
3.
Set another programmable output to follow the timeout of the time-overcurrent
element timeout via the 51NT bit in the Relay Word. Use the assertion of this
output to stop the external timer.
4.
Calculate the expected operating time of the 51NT element using the appro-
priate equation for the curve number. This is dictated by the relay 51NC
setting. TD is the relay 51ND time dial setting. M is the multiple of pickup
current to be applied to the relay. Using example relay settings and a current
multiple of pickup equal to three, the equation for the very inverse curve (2) is:
where
M = Multiples of Pickup = 3
TD = Time Dial = 3
7-30
Maintenance & Testing
SEL-221F, -1 Instruction Manual
Date Code 920508
Summary of Contents for SEL-221F
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Page 110: ...Example Event Report 2 4 12 Event Reporting SEL 221F 1 Instruction Manual Date Code 930830 ...
Page 158: ...SETTINGS SHEET FOR SEL 221F RELAY PAGE 2 OF 6 DATE Date Code 921110 ...
Page 160: ...SETTINGS SHEET PAGE 4 OF 6 FOR SEL 221F RELAY DATE Date Code 930601 ...
Page 161: ...SETTINGS SHEET PAGE 5 OF 6 FOR SEL 221F RELAY DATE Date Code 961208 ...
Page 229: ...SEL 200 Series Relay Main Board Troubleshooting Test Points and Jumper Locations ...