108
Current protection Chapter 11
Verifying settings by secondary
injection
13. Continue to test another function or end the test by changing the test
mode setting to off.
6.7 Breaker failure protection (RBRF, 50BF)
Prepare the IED for verification of settings as outlined in section 1 "Overview" and section 2
"Preparing for test" in this chapter.
The breaker-failure protection should normally be tested in conjunction with some other func-
tion that provides a start signal. An external start signal can also be used.
The function(s) has to be set and configured before the testing can start. The BFP function is
highly flexible in that it permits a choice of functional and tripping modes. The various modes
are checked at the factory as part of the design verification. In certain cases only modes with a
high probability of coming into operation need to be checked, in order to verify the configuration
and settings.
Required for testing the function are:
• Calculated settings
• Valid configuration diagram for the IED
• Valid terminal diagram for the IED
• Technical reference manual
• Three-phase test equipment
The Technical reference manual contains application and functionality summaries, function
blocks, logic diagrams, input and output signals, a list of setting parameters and technical data
for the function.
The test equipment should be able to provide a three-phase supply of currents (and for some start
functions also voltage). The magnitude and angle of currents (and voltages) should be possible
to vary.
Make sure the IED is prepared for test before starting the test session. Consider the logic diagram
of the function when performing the test. The response from a test can be viewed in different
ways:
• Binary output signals
• Service values in the local HMI (logical signal or phasors)
• A PC with PCM600 (configuration software) in debug mode
To verify the settings in the most common back-up trip mode “1 out of 3” it is sufficient to test
phase-to-earth faults.
At mode “2 out of 4” the Phase current setting, IP> can be checked by single phase injection
where the return current is connected to the summated current input. The value of residual (EF)
current “IN” set lower than IP> is easiest checked in back-up trip mode “1 out of 4”.
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