6.
Check that the START signal resets.
7.
Instantaneously decrease the frequency of the applied voltage to a value about
20% lower than the nominal value.
8.
Measure the time delay for the TRIP signal, and compare it with the set value.
Extended testing
1.
The test above can be repeated to check a positive setting of
StartFreqGrad
.
2.
The tests above can be repeated to test the RESTORE signal, when the
frequency recovers from a low value.
6.5.3.2
Completing the test
Continue to test another function or end the testing by setting the parameter
TestMode
to
Off
under
Main menu/Tests/IED test mode/1:TESTMODE
. If
another function is tested, then set the parameter
Blocked
to
No
under
Main menu/
Tests/Function test modes/Frequency/SAPFRC(81,df/dt)/X:SAPFRC
for the
function, or for each individual function in a chain, to be tested next. Remember to
set the parameter
Blocked
to
Yes
, for each individual function that has been tested.
6.6
Testing secondary system supervision functions
6.6.1
Current circuit supervision CCSRDIF
Prepare the IED for verification of settings as outlined in
.
The Current circuit supervision function CCSRDIF is conveniently tested with the
same three-phase test set as used when testing the measuring functions in the IED.
The condition for this procedure is that the setting of
IMinOp
is lower than the
setting of
Ip>Block
.
6.6.1.1
Verifying the settings
1.
Check the input circuits and the operate value of the
IMinOp
current level
detector by injecting current, one phase at a time.
2.
Check the phase current blocking function for all three phases by injection
current, one phase at a time. The output signals shall reset with a delay of 1
second when the current exceeds 1.5 ·
IBase
.
3.
Inject a current 0.9 ·
IBase
to phase L1 and a current 0.15 ·
IBase
to the
reference current input IREFSMPL.
4.
Decrease slowly the current to the reference current input and check that
blocking is obtained when the current is about 0.1 ·
IBase
.
1MRK 511 248-UEN -
Section 6
Testing functionality
67
Commissioning Manual
