114
Current protection Chapter 11
Verifying settings by secondary
injection
6.8.1 Measuring the operate limit of set values
Procedure
1. Check that the input logical signals BLOCK and RELEASE are logi-
cal zero and note on the local HMI that the TRIP logical signal is
equal to the logical 0.
Logical signals for STUB protection are available under menu tree:
Measurements\Current protection\Stub\STB
2. Activate the RELEASE binary input.
STUB protection settings are available under menu tree:
Settings\Setting group N\Current protection\Stub\STB
3. Quickly set the measured current (fault current) in one phase to
about 110% of the set operating current, and switch the current off
with the switch.
Observe the maximum permitted overloading of the current circuits in the
IED.
4. Switch the fault current on and measure the operating time of the
STUB protection.
Use the TRIP signal from the configured binary output to stop the timer.
The operation should be instantaneously.
5. Activate the BLOCK binary input.
6. Switch on the fault current (110% of the setting).
No TRIP signal should appear.
7. Switch off the fault current.
8. Quickly set the measured current (fault current) in same phase to
about 90% of the set operating current, and switch the current off
with the switch.
9. Switch the fault current on.
No TRIP signal should appear.
10. Switch the fault current off.
11. Reset the RELEASE binary input.
12. Switch the fault current on.
No TRIP signal should appear.
13. Switch the fault current off.
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