13.4
SEL-311C Relay Instruction Manual Date Code 20060320
Testing and Troubleshooting
Testing Philosophy
At the end of your maintenance interval, the only items that need testing are
those that have not operated during the maintenance interval.
The basis of this testing philosophy is simple: If the relay is correctly set and
connected, is measuring properly, and no self-test has failed, there is no reason
to test it further.
Each time a fault occurs, the protection system is tested. Use event report data
to determine areas requiring attention. Slow breaker auxiliary contact
operations and increasing or varying breaker operating time can be detected
through detailed analysis of relay event reports.
Because SEL relays are microprocessor based, their operating characteristics
do not change over time. Time-overcurrent operating times are affected only
by the relay settings and applied signals. It is not necessary to verify operating
characteristics as part of maintenance checks.
At SEL, we recommend that maintenance tests on SEL relays be limited under
the guidelines provided above. The time saved may be spent analyzing event
data and thoroughly testing those systems that require more attention.
To Next Page
Loading...
