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U.6.8
SEL-421/SEL-421-1 Relay
User’s Guide
Date Code 20020501
Testing and Troubleshooting
Testing Features and Tools
Main Board Processing Module Tests
Use signals from the SEL-4000 Low-Level Relay Test System to test the relay
processing module. Apply appropriate signals to the low-level test interface
J20 from the SEL-4000 Relay Test System (see
These signals simulate power system conditions, taking into account PT ratio
and CT ratio scaling. Use relay metering to determine whether the applied test
voltages and currents produce correct relay operating quantities.
The UUT Database entries for the SEL-421 Relay in the SEL-5401 Relay Test
System Software are shown in
Table 6.4
UUT Database Entries for
SEL-5401 Relay Test System Software—5 A Relay
Label
Scale Factor
Unit
1
IAW
75
A
2
IBW
75
A
3
ICW
75
A
4
IAX
75
A
5
IBX
75
A
6
ICX
75
A
7
VAY
150
V
8
VBY
150
V
9
VCY
150
V
10
VAZ
150
V
11
VBZ
150
V
12
VCZ
150
V
Table 6.5
UUT Database Entries for
SEL-5401 Relay Test System Software—1 A Relay
Label
Scale Factor
Unit
1
IAW
15
A
2
IBW
15
A
3
ICW
15
A
4
IAX
15
A
5
IBX
15
A
6
ICX
15
A
7
VAY
150
V
8
VBY
150
V
9
VCY
150
V
10
VAZ
150
V
11
VBZ
150
V
12
VCZ
150
V
Summary of Contents for SEL-421
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