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1MRK 506 355-UEN A
10.5.4.3
10.5.5
Line distance protection REL670 2.1 IEC
Commissioning manual
Testing functionality by secondary injection
Completing the test
Continue to test another function or end the test by changing the TestMode setting to
Off. Restore connections and settings to their original values, if they were changed for
testing purposes.
Four step negative sequence overcurrent protection
NS4PTOC
Prepare the IED for verification of settings as outlined in section
section
"Preparing for test"
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.
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 be activated. Check under NS4PTOC function Service Values
that correct I2 magnitude is measured by the function.
3.
Set the injected negative sequence polarizing voltage slightly larger than the set
minimum polarizing voltage (default 5 % of Ub) and set the injection current to
lag the voltage by an angle equal to the set reference characteristic angle (180°
- AngleRCA) if the forward directional function is selected.
If reverse directional function is selected, set the injection current to lag the
polarizing voltage by an angle equal to RCA.
4.
Increase the injected current and note the value at which the studied step of the
function operates.
5.
Decrease the current slowly and note the reset value.
6.
Block lower set steps when testing higher set steps according to the instructions
that follow.
7.
Connect a trip output contact to a timer.
8.
Set the injected current to 200% of the operate level of the tested step, switch on
the current and check the time delay.
For inverse time curves, check the operate time at a current equal to 110% of the
operate current in order to test parameter txmin.
9.
Check that all operate and start contacts operate according to the configuration
(signal matrixes)
10. Reverse the direction of the injected current and check that the step does not
operate.
in this chapter.
Section 10
"Requirements"
and
149
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