13.6 Current protection
13.6.1
Instantaneous phase overcurrent protection PHPIOC
Prepare the IED for verification of settings as outlined in section
"Overview" and
section "Preparing for test" in this chapter.
To verify the settings the following fault type should be tested:
•
Phase-to-earth fault
Ensure that the maximum continuous current, supplied from the current source
used for the test of the IED, does not exceed four times the rated current value of
the IED.
13.6.1.1 Measuring the operate limit of set values
1. Inject a phase current into the IED with an initial value below that of the setting.
2. Set the operation mode to 1 out of 3.
3. Increase the injected current in the Ln phase until the TRL (n=1–3) signal
appears.
4. Switch the fault current off.
Observe: Do not exceed the maximum permitted overloading
of the current circuits in the IED.
5. Compare the measured operating current with the set value.
6.
Set the operation mode to 2 out of 3 and inject current into one of the phases.
Check - no operation.
13.6.1.2 Completing the test
Continue to test another function or end the test by changing the Test mode setting
to Off. Restore connections and settings to their original values, if they were
changed for testing purposes.
13.6.2 Four step phase overcurrent protection OC4PTOC
Prepare the IED for verification of settings outlined in section
"Overview" and
section "Preparing for test" in this chapter.
13.6.2.1
Verifying the settings
1MRK 504 088-UEN C Section 13
Verifying settings by secondary injection
135
Installation and commissioning manual
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