Completing The Test; Negative-Sequence Time Overcurrent Protection For Machines Ns2Ptoc; Verifying Settings By Secondary Injection - ABB Relion 670 Series Commissioning Manual

Section 11
Testing functionality by secondary injection
11.5.15.2

Completing the test

Continue to test another functions or end the test by changing the Test mode setting to
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.
11.5.16 Negative-sequence time overcurrent protection for machines
NS2PTOC
11.5.16.1

Verifying settings by secondary injection

1. Connect the test set for injection of three-phase currents to the appropriate current
terminals of the IED.
2. Go to Main menu/Settings/IED Settings/Current protection/NegSeqOverCurr2Step/
NSOn/General and make sure that the function is enabled, that is
3. Inject current into IEDs in such a way that negative sequence component is created and
then verify that negative sequence component of the injected currents is calculated
correctly by the function. See example below for 1 A rated current transformer.
4. 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 start level. No output signals should be
activated.
Note: If it is difficult to obtain pure negative sequence current for the secondary injection
test, a current corresponding to the two phase short-circuit condition can be used. A two
phase short-circuit gives a negative sequence current of a magnitude: magnitude =
(1/√3) · fault current.
5. Increase the injected current and note the value at which the step 1 of the function
operates. Start signal ST1 must be activated when amplitude of the negative sequence
current lies slightly above the start level
activated after the pre-set time delay has expired.
Note: Block or disable operation of step 2 when testing step 1 if the injected current
activates the step 2.
6. Decrease the current slowly and note the reset value.
7. Connect a trip output contact to a timer.
8. Set the current to 200% of the start level of the step 1, switch on the current and check
the definite time delay for trip signals TR1 and TRIP. Once the measured negative
sequence current exceeds the set start level
count and trip signals is released after the set time delay has elapsed. The same test
must be carried out to check the accuracy of definite time delay for ALARM signal.
Note: The output ALARM is operated by START signal.
9. If inverse time is selected the trip signals TR1 and TRIP operates after a time
corresponding to the formula:
186
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.
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I2-1> . Corresponding trip signals TR1 and TRIP is
I2-1> , the settable definite timer t1 starts to
Transformer protection RET670
1MRK 504 165-UEN E
GUID-5AB7880E-629C-45E5-AF91-3EBDF19DEA79 v2
Off .
GUID-48A6DA1D-5CF5-4C1B-B1A4-3F2C73851FD4 v2
GUID-F7AA2194-4D1C-4475-8853-C7D064912614 v4
GUID-EB788169-532A-4A3E-BBEC-DCB28169DF86 v7
Operation is set to On .
Commissioning manual