13.3
Date Code 20060320 Instruction Manual SEL-311C Relay
Testing and Troubleshooting
Testing Philosophy
SEL performs a complete functional check and calibration of each relay
before it is shipped. This helps ensure that you receive a relay that operates
correctly and accurately.
Step 1. Commissioning tests should verify that the relay is properly
connected to the power system and all auxiliary equipment.
Step 2. Verify control signal inputs and outputs.
Step 3. Check breaker auxiliary inputs, SCADA control inputs, and
monitoring outputs.
Step 4. Use an ac connection check to verify that the relay current and
voltage inputs are of the proper magnitude and phase rotation.
Step 5. Brief fault tests ensure that the relay settings are correct.
It is not necessary to test every relay element, timer, and
function in these tests.
Step 6. At commissioning time, use the relay METER command to
verify the ac current and voltage magnitude and phase rotation.
Step 7. Use the PULSE command to verify relay output contact
operation.
Step 8. Use the TARGET command to verify optoisolated input
operation.
Maintenance Testing
1. When:
a. At regularly scheduled intervals or when there is an
indication of a problem with the relay or system.
2. Goals:
a. Ensure that the relay is measuring ac quantities
accurately.
b. Ensure that scheme logic and protection elements are
functioning correctly.
c. Ensure that auxiliary equipment is functioning
correctly.
3. What to test:
a. Anything not shown to have operated during an actual
fault within the past maintenance interval.
SEL relays use extensive self-testing capabilities and feature detailed metering
and event reporting functions that lower the utility dependence on routine
maintenance testing.
Use the SEL relay reporting functions as maintenance tools.
Step 1. Periodically verify that the relay is making correct and accurate
current and voltage measurements by comparing the relay
METER output to other meter readings on that line.
Step 2. Review relay event reports in detail after each fault.
Step 3. Using the event report current, voltage, and relay element data,
you can determine that the relay protection elements are
operating properly.
Step 4. Using the event report input and output data, you can determine
that the relay is asserting outputs at the correct instants and that
auxiliary equipment is operating properly.
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