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1MRK 505 372-UEN Rev. K
Above procedure can also be used to test definite time step. Pay attention that IDMT step can also
operate during such injection. Therefore make sure that appropriate settings are entered in order to
insure correct test results for definite time step.
10.4.11.2
Completing the test
Continue to test another functions 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. Make
sure that all built-in features for this function, which shall be in operation, are enabled and with
correct settings.
10.5
Voltage protection
10.5.1
Two step undervoltage protection UV2PTUV
Prepare the IED for verification of settings as outlined in section
section
10.5.1.1
Verifying the settings
Verification of start value and time delay to operate for Step 1
1.
Check that the IED settings are appropriate, especially the START value, the definite time delay
and the 1 out of 3 operation mode.
2.
Supply the IED with three-phase voltages at their rated values.
3.
Slowly decrease the voltage in one of the phases, until the START signal appears.
4.
Note the operate value and compare it with the set value.
For phase-to-earth measurement:
U
1
100
IECEQUATION2430 V1 EN-US
For phase-to-phase measurement:
U
1
100
IECEQUATION2431 V1 EN-US
5.
Increase the measured voltage to rated load conditions.
6.
Check that the START signal resets.
7.
Instantaneously decrease the voltage in one phase to a value about 20% lower than the
measured operate value.
8.
Measure the time delay for the TRIP signal, and compare it with the set value.
9.
Check the inverse time delay by injecting a voltage corresponding to 0.8 × U1<.
Busbar protection REB670
Commissioning manual
Note that it is recommended to test IDMT operating times by injected current with the
rated frequency.
"Preparing for test"
in this chapter.
The operate value in secondary volts is calculated according to the following
equations:
UBase VT
sec
<
×
×
VTprim
3
VT
sec
<
UBase
×
×
VTprim
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Testing functionality by secondary injection
GUID-5AB7880E-629C-45E5-AF91-3EBDF19DEA79 v2
"Requirements"
and
Section 10
SEMOD53540-1 v1
M13796-2 v6
M13796-9 v3
M13796-29 v11
(Equation 15)
(Equation 16)
99
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