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Section 12
Testing functionality by secondary injection
12.3.3.2
12.3.4
12.3.4.1
108
as the generator differential protection, are set off. Make sure that the generator
differential function is unblocked.
2.
Connect the test set for injection of three-phase current to the current IEDs,
which are connected to the CTs on the HV side of the generator.
3.
Increase the current in phase L1 until the protection function operates and note
the operating current.
4.
Check that trip and alarm contacts operate according to the configuration logic.
5.
Decrease the current slowly from operate value and note the reset value.
6.
Check in the same way the function by injecting current in phases L2 and L3.
7.
Inject a symmetrical three-phase current and note the operate value.
8.
Connect the timer and set the current to twice the operate value.
9.
Switch on the current and note the operate time.
10. Check in the same way the functioning of the measuring circuits connected to the
CTs on the neutral point side of the generator.
11. Finally check that trip information is stored in the event menu.
Information on how to use the event menu is found in the
operator's manual.
12. If available on the test set a second-harmonic current of about 20% (assumes
15% setting on I1/I2 ratio parameter) can be added to the fundamental tone in
phase L1. Increase the current in phase L1 above the start value measured in step
3. Repeat test with current injection in phases L2 and L3 respectively.
Fifth-harmonic blocking can be tested in a similar way.
The balancing of currents flowing into and out of the differential zone is
typically checked by primary testing.
Completing the test
Continue to test another function or end the test by changing the TestMode setting to
Off. Restore connections and settings to their original values, if they were changed for
testing purposes.
Restricted earth-fault protection, low impedance REFPDIF
Prepare the IED for verification of settings outlined in section
section
"Preparing for test"
Verifying the settings
1.
Connect the test set for single-phase current injection to the protection terminals
connected to the CT in the power transformer neutral-to-earth circuit.
2.
Increase the injection current and note the operating value of the protection
function.
3.
Check that all trip and start contacts operate according to the configuration logic.
in this chapter.
1MRK502053-UEN B
"Requirements"
Generator protection REG670 2.0 IEC
Commissioning manual
and
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Table of Contents
Troubleshooting
