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U.6.20
SEL-421/SEL-421-1 Relay
User’s Guide
Date Code 20020501
Testing and Troubleshooting
Test Methods
Step 8. Test the element. Increase the current source to produce a
current magnitude greater than 10.00 A secondary in the relay.
When the 50P1 element picks up, the relay changes the 50P1
Relay Word bit to logical 1 and closes the output contacts of
control output OUT105. The indicating device operates.
Testing With SER
You can set the relay to generate a report from the SER to test relay elements;
include the element that you want to test in the SER Points and Aliases list.
Set aliases for the element name, set state, and clear state in the SEL-421
Relay SER to simplify reading the SER report. See
Recorder) on page A.3.34 in the Applications Handbook
for complete
information on the SER.
Testing the 51S1 Element Using the SER
The SER gives exact time data for testing time-overcurrent element timeouts.
Subtract the 51S1T assertion time from the 51S1 assertion time to check the
operation time for this element. Use the factory defaults for the operating
quantity, pickup level, curve, time dial, and electromechanical reset
(
).
The procedure in the following steps shows how to set the SER trigger lists to
capture the selectable operating quantity time-overcurrent element 51S1
operating times. The procedure also shows how to set the torque control
supervision for the 51S1 element.
The relay uses
and
to determine the operating time
for the 51S1 element. For a current input 50 percent greater than the default
pickup, the test value, I
TEST,
is:
Equation 6.1
where M is the pickup multiple and 51S1P is the element pickup value (see
Table 6.7
Selectable Operating Quantity
Time-Overcurrent Element (51S1) Default Settings
Setting
Description
Default 5A
51S1O
51S1 Operating Quantity (IA
n
, IB
n
, IC
n
, IMAX
n
, I1L,
3I2L, 3I0L)
a
a
n is L, 1, and 2 for Line, Circuit Breaker 1, and Circuit Breaker 2, respectively.
3I0L
51S1P
51S1 Overcurrent Pickup (0.50–16 amps, secondary)
0.75
51S1C
51S1 Inv-Time Overcurrent Curve (U1–U5, C1–C5)
U3
51S1TD
51S1 Inv-Time Overcurrent Time Dial (0.50–15.0)
1.0
51S1RS
51S1 Inv-Time Overcurrent EM Reset (Y, N)
N
51S1TC
51S1 Torque Control (SEL
OGIC
control equation)
32GF
I
TEST
M • (51S1P)
1.5 • (0.75 A)
1.125 A
=
=
=
Summary of Contents for SEL-421
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