ISA T1000 PLUS User Manual page 84

DOC. MIE91093 Rev. 1.34 Page 84 of 145
The first fault starts the sequence. The CB opens after D1, and
then closes after R1. The test set automatically injects fault
No. 2 after the programmed TD, that is more than TDr: the CB
opens and closes again. If N = 1, the sequence is completed;
else, tests will continue until fault N+1 is generated, followed
by open N+1 and reclose N+1.
. Second test: TD is programmed smaller than the set
reclaim TDr, for instance 0.95*TDr. Program the number of
tests N foreseen by the CB's Recloser. As the fault arrives
before the reclaim time is expired, after N+1 faults, the CB
must not close. This behavior confirms that faults occur before
TDr has expired. The following time diagram explains the test
evolution.
The second test allows also to verify the reclose timings RX,
and the number of reclose commands, N.
FAULT
1
N+1
2
CLOSED
CB POS
OPEN
D1 R1 >TDr
The first fault starts the sequence. The relay trips after D1;
the CB closes after R1. The test set automatically injects fault
No. 2 after the programmed TD, that is less than TDr. If N =
1, the sequence is completed; else, tests will continue until
fault N+1 is generated, followed by open N+1, but no close
N+1; the CB will remain open.
The test set waits for the last close for a time equal to 10
times the last measured RX delay; then, the sequence is
finished.
The two tests together allow verifying TDr with the set
accuracy (for instance, 5%).