This means that if the measured phase current jumps from 0 to 2 times the set trip level and time
multiplier k is set to 1.0 s (default value), then the TROC and TRIP signals will trip after a time delay
equal to 13.5 s ± tolerance.
Taking into account the above explanation, inject the voltages related to the last part of the
characteristic and inject a current IA 200% higher than the set operation level, and check the trip
time delay.
If tDef_OC is set to a value different from 0 s, then this time delay is added to the
one that is defined by the IDMT characteristic.
10. Check the pickup and trip information that are stored in the event menu.
11. The previous step 8 or 9 may be repeated also for the first and second section of the characteristic.
12. Supply the IED with symmetric three-phase voltages at their rated values. Go to Main menu /
Settings /IED Settings /Current protection /VoltageRestOverCurr(51V,2(I>/V<)) /
VRPVOC(51V,2(I>/V<)):1 /Undervoltage and set the setting Operation_UV = Enabled to activate
the undervoltage stage.
13. Slowly decrease the voltage in two phases simultaneously, until the STUV and PICKUP signals
appear.
14. Note the trip value. The set trip value in secondary volts is calculated according to the following
equation:
Pickup Volt VBase VT
VTprim
_ sec
100
3
× ×
ANSIEQUATION2436 V2 EN-US (Equation 99)
If the VRPVOC function is used as an overcurrent protection with undervoltage
seal-in, it is necessary to first inject sufficient current to activate the STOC signal
before the under-voltage step is allowed to trip. In order to achieve that, apply
symmetric three-phase voltages at their rated value and then inject a current IA
that is 200% higher than the set tripping level. Then slowly decrease the voltage in
two phases simultaneously, until the STUV and PICKUP signals appear.
15. Increase slowly the applied voltages of the previous two phases and note the reset value.
16. Check that the trip output of the relay is connected to the input channel of the test in order to stop
the injection and measure the trip time.
17. Inject symmetric three-phase voltages at their rated value and check that the STUV and PICKUP
signals reset as well as the trip signals of the function block (TRIP and TRUV).
18. Instantaneously decrease the voltage in two phases simultaneously to a value 20% lower than the
set trip value (take into account the previous note if VRPVOC is configured in ACT with the
undervoltage seal-in feature).
19. Measure the definite time delay for the TRUV and TRIP signals and compare it with the set value
tDef_UV.
20. Check that pickup and trip information is stored in the event menu.
11.5.18.3 Completing the test
GUID-8A33AACE-7B89-4981-A872-78044BB1FD0D v2
Continue to test another function or end the test by changing the TESTMODE setting to Disabled.
Restore connections and settings to the original values, if changed for testing purposes.
11.5.19 Average Power Transient Earth Fault Protection, APPTEF
GUID-079BCF22-469C-42EA-B857-E28154EC13D9 v1
Prepare the IED for verification of settings outlined in Section
"Preparing the IED to verify settings".
Section 11 1MRK 504 165-UUS Rev. J
Testing functionality by secondary injection
200 Transformer protection RET670
Commissioning manual
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