Schweitzer Engineering Laboratories SEL-351-5, Instruction Manual

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13.2
SEL-351-5, -6, -7 Relay Instruction Manual
Date Code 20070117
Testing and Troubleshooting
Testing Philosophy
Testing Philosophy
Protective relay testing may be divided into three categories:
➤
acceptance
➤
commissioning
➤
maintenance
The categories are differentiated by when they take place in the life cycle of
the relay as well as in the test complexity.
The paragraphs below describe when to perform each type of test, the goals of
testing at that time, and the relay functions that you need to test at each point.
This information is intended as a guideline for testing SEL relays.
Acceptance Testing
When: When qualifying a relay model to be used on the utility system.
Goals:
1. Ensure relay meets published critical performance
specifications such as operating speed and element accuracy.
2. Ensure that the relay meets the requirements of the intended
application.
3. Gain familiarity with relay settings and capabilities.
What to test: All protection elements and logic functions critical to the
intended application.
SEL performs detailed acceptance testing on all new relay models and
versions. We are certain the relays we ship meet their published specifications.
It is important for you to perform acceptance testing on a relay if you are
unfamiliar with its operating theory, protection scheme logic, or settings. This
helps ensure the accuracy and correctness of the relay settings when you issue
them.
Commissioning
Testing
When: When installing a new protection system.
Goals:
1. Ensure that all system ac and dc connections are correct.
2. Ensure that the relay functions as intended using your settings.
3. Ensure that all auxiliary equipment operates as intended.
What to test: All connected or monitored inputs and outputs, polarity and
phase rotation of ac connections, simple check of protection elements.
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. Commissioning tests should verify that the relay is
properly connected to the power system and all auxiliary equipment. Verify
control signal inputs and outputs. Check breaker auxiliary inputs, SCADA
control inputs, and monitoring outputs. Use an ac connection check to verify
that the relay current and voltage inputs are of the proper magnitude and phase
rotation.
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.