For inverse time curves, check the trip time at a current equal to 110% of the trip
current for txMin.
9. Check that all trip and pickup contacts trip according to the configuration (signal
matrixes)
10. Reverse the direction of the injected current and check that the step does not trip.
11. Check that the protection does not trip when the polarizing voltage is zero.
12. Repeat the above described tests for the higher set steps.
13. Finally, check that pickup and trip information is stored in the event menu.
11.5.4.2 Four step non-directional ground fault protection
1. Do as described in
"Four step directional ground fault protection", but without
applying any polarizing voltage.
11.5.4.3 Completing the test
Continue to test another function or end the test by changing the TESTMODE setting to
Disabled. Restore connections and settings to their original values, if they were changed
for testing purposes.
11.5.5 Four step negative sequence overcurrent protection NS4PTOC
(46I2)
Prepare the IED for verification of settings as outlined in section
"Preparing for test" in
this chapter.
When inverse time overcurrent characteristic is selected, the trip time of
the stage will be the sum of the inverse time delay and the set definite time
delay. Thus, if only the inverse time delay is required, it is important to set
the definite time delay for that stage to zero.
Procedure
1. Connect the test set for injection of three-phase currents and voltages to the
appropriate CT and VT inputs of the IED.
2. Inject pure negative sequence current, that is, phase currents with exactly same
magnitude, reversed sequence and exactly 120° phase displaced into the IED with an
initial value below negative sequence current pickup level. No output signals should
Section 11 1MRK 504 165-UUS -
Testing functionality by secondary injection
182 Transformer protection RET670 2.2 ANSI
Commissioning manual
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