Completing The Test; Negative-Sequence Time Overcurrent Protection For Machines Ns2Ptoc; Verifying Settings By Secondary Injection - ABB RET670 Commissioning Manual

1MRK 504 165-UEN A
11.5.14.2
11.5.15
11.5.15.1
Transformer protection RET670 2.2 IEC
Commissioning manual
Testing functionality by secondary injection
frequency. Note that for the fundamental frequency injection, internally calculated
voltage in percent corresponds directly to the injected current value given in
percent. However if it is required to test IDMT characteristic with a varying
frequency, the magnitude of the injected current must be adjusted accordingly. The
following formula can be used to calculate required current RMS value in percent
at the desired injection frequency in order to archive voltage percentage value
given in the above table:
f
[ ]
[ ]
%
= injected ×
I % U
inj
f
rated
EQUATION2274 V1 EN-US
Note that it is recommended to test IDMT operating times by
injected current with the rated frequency.
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.

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.
Negative-sequence time overcurrent protection for
machines NS2PTOC
When inverse time overcurrent characteristic is selected, the
operate 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.

Verifying settings by secondary injection

Section 11
(Equation 90)
GUID-5AB7880E-629C-45E5-AF91-3EBDF19DEA79 v2
GUID-48A6DA1D-5CF5-4C1B-B1A4-3F2C73851FD4 v2
GUID-F7AA2194-4D1C-4475-8853-C7D064912614 v4
GUID-EB788169-532A-4A3E-BBEC-DCB28169DF86 v6
199