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 I2-1>, the
settable definite timer t1 starts to 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:
t s
I
[ ]
( )
=
− >
⋅
1
2 1
100
2
2
Multiple of Start
KK
This means that if current jumps from 0 to 2 times start and negative
sequence capability value of generator K1 is set to 10 sec and current start
level I2-1> is set to 10% of rated generator current, then TR1 and TRIP
signals operates at time equal to 250 sec ± tolerance.
10. Repeat the above-described tests for the step 2 of the function excluding the
inverse time testing.
11. Finally check that start and trip information is stored in the event menu.
Example
The CT ratios
for all three phases is 1000 A, IBase is 1000 A, and the
following secondary currents are applied:
IL1
Ampl = 1.1 A Angl = 15 deg
IL2 Ampl = 0.6 A Angl = 97 deg
IL3 Ampl = 1.3 A Angl = -135 deg
The service value output NSCURR indicating amplitude of negative sequence
current in primary amperes should be 962A approximative.
15.6.12.2 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.
Section 15 1MRK 502 029-UEN A
Verifying settings by secondary injection
190
Installation and commissioning manual
To Next Page
Loading...
