8.
.
9.
Connect the nominal voltages in all three phases and feed a current below the
operate level in all three phases.
10. Keep the current constant. Disconnect the voltage in all three phases
simultaneously.
The BLKU, BLKZ and 3PH signals should not appear.
6.6.2.5
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/Secondary system supervision/SDDRFUF/
1:SDDRFUF
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.
6.7
Testing control functions
The save of persistent parts of function block states/values to
persistent memory uses an exponential back-off algorithm, which
rapidly increases the time between save operations when there are
frequent changes in such states/values. This means, that when e.g. a
pulse counter is exercised periodically, the time between saves of
its counter value to persistent memory will occur more and more
seldom until there is one hour between save operations. If the IED
is restarted by turning auxiliary power off and back on, then up to
one hour of counter value increments will be lost. This back-off
algorithm is necessary to avoid wearing out the FLASH memory
that is used to save the states/values. When changing parameter
values using LHMI or PST, there is a save of this type of memory
before rebooting, so in this case normally no information is lost.
When there are long periods of inactivity, the time between save
operations decreases slowly again, until it reaches the minimum
time between saves, which is approximately once per second. After
commissioning is complete, the possible loss of information should
not be an issue, since in normal operation an IED is switched off
extremely seldom. But during certain tests, if the IED is rebooted,
then data of this kind will sometimes revert back to old values.
6.7.1
Synchrocheck, energizing check, and synchronizing
SESRSYN
1MRK 511 248-UEN -
Section 6
Testing functionality
71
Commissioning Manual
