Date Code 20001006 Testing and Troubleshooting 13-1
SEL-351 Instruction Manual
SECTION 13: TESTING AND TROUBLESHOOTING
INTRODUCTION
This section provides guidelines for determining and establishing test routines for the SEL-351
Relay. Included are discussions on testing philosophies, methods, and tools. Relay self-tests and
troubleshooting procedures are shown at the end of the section.
TESTING PHILOSOPHY
Protective relay testing may be divided into three categories: acceptance, commissioning, and
maintenance testing. 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: a) Ensure relay meets published critical performance specifications such as operating
speed and element accuracy.
b) Ensure that the relay meets the requirements of the intended application.
c) 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: a) Ensure that all system ac and dc connections are correct.
b) Ensure that the relay functions as intended using your settings.
c) 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.
Courtesy of NationalSwitchgear.com
To Next Page
