Date Code 20020501
User’s Guide
SEL-421/SEL-421-1 Relay
Section 6
UUser’s Guide
Testing and Troubleshooting
This section contains guidelines for determining and establishing test routines
for the SEL-421 Relay. Follow the standard practices of your company in
choosing testing philosophies, methods, and tools. The relay incorporates self-
tests to help you diagnose potential difficulties should these occur. The
subsection
Relay Troubleshooting on page 6.40
contains a quick-reference
table for common relay operation problems.
Topics, tests, and troubleshooting procedures presented in this section include
the following:
➤
Testing philosophy
➤
Testing features and tools
➤
Relay test connections
➤
Test methods
➤
Relay element tests (selected elements)
➤
Relay self-tests
➤
Relay troubleshooting
➤
Factory assistance
The SEL-421 Relay is factory calibrated; this section contains no calibration
information. If you suspect that the relay is out of calibration, contact your
Technical Service Center or the SEL factory.
Summary of Contents for SEL-421
Page 8: ...This page intentionally left blank ...
Page 30: ...This page intentionally left blank ...
Page 110: ...This page intentionally left blank ...
Page 204: ...This page intentionally left blank ...
Page 284: ...This page intentionally left blank ...