Basler BE1-CDS220, Instruction Manual

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BE1-CDS220 Testing And Maintenance 13-27
PERIODIC TESTING
Because the relay has extensive internal self test capabilities, periodic testing of the protection system can
be greatly reduced. The relay characteristics are a function of the programming instructions that do not
drift over time. Thus, the user may wish to verify that the:
•
Set points that were proven during the commissioning have not been changed.
•
Inputs and outputs are properly interfacing with the rest of the protection and control system.
•
Power system analog parameters used by the protection and control functions are being
measured accurately.
These are things that the self test capability cannot completely determine.
Settings Verification
Verification of the relay settings can be accomplished in several ways depending upon the user’s
preferences and practices. This step may not be required if the settings changed alarm point is
programmed to an output and is being monitored. This way, any unexpected setting changes would be
logged and investigated. Some settings verification possibilities include:
•
Repeating the Protection and Control Function commissioning tests.
•
If a file of the settings recorded upon commissioning is available, the settings can be read out of
the relay and captured to a similar file and compared using software tools.
•
The settings can be verified by simple inspection of the settings versus those recorded upon
commissioning.
Digital I/O Connection Verification
Verification of the relay digital I/O connections can be accomplished in several ways depending upon the
user’s preferences and practices.
•
Repeating the digital I/O connection verification commissioning tests.
•
Monitoring SER, Status, and Fault reports for proper sensing of digital signals and proper tripping
during normal operation.
NOTE
If protection systems are redundant such that multiple relays will trip a given breaker or
device for a fault, simply monitoring fault reports may not indicate a failed output contact.
The relay may report that it energized an output. However, tripping was actually
accomplished by the redundant relay. With this situation, actually testing the contact is
recommended.
Analog Circuit Verification
NOTE
If you are going to verify the analog measurement circuits by comparison to independent
devices, you should ensure that the two devices use similar measurement algorithms. For
example, the measurements of a fundamental sensing relay cannot be compared with the
measurements of an RMS sensing device.
Verification of the relay analog measurement circuits can be accomplished in several ways depending
upon the user’s preferences and practices. Some of these ways are:
•
Repeating portions of the acceptance or commissioning tests and injecting known test signals into
the relay.
•
Using the metering functions of the relay and comparing the measurements to those provided by
other similar devices that are measuring the same signals. Redundant relays and/or metering
devices can provide this source of independent conformation of the measured signals. If the relay
is connected to an integration system, this can even be automated and done on a routine basis.