Alstom SHPM 101, Руководство по обслуживанию

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SERVICE MANUAL R5888C
QUADRAMHO Chapter 5
Page 13 of 24
Now with the opto coupler still energised, apply a Zone 1 ground fault, a Zone 2
phase fault and a Zone 3 reverse (if offset) earth fault. No operation should occur.
De-energise the MCB opto coupler and normal operation will occur but note the
VTS light requires resetting.
4.14 Switch-on-to-fault check
The feature is enabled when all poles (volts and current) have been dead or the
breaker open opto isolator is energised for either 200ms or 110ms as selected by
switch SW2. (To the right gives 200ms).
When the poles dead signal ceases the feature remains available for 240ms.
Switch SW1 controls the method of detecting a switch-on-to-fault:
i) With SW1 to the right, a trip is caused by a current being detected above the
low set phase current level detector threshold and volts being below the voltage
level detector setting on the same phase.
ii) With SW1 to the left, a trip is caused by the operation of any Zone 1, Zone 2
or Zone 3 comparator.
It should be noted that no phase indication is given; only the SOTF LED will
illuminate and a 3 phase trip with auto reclose blocked occurs. A time delay of
20ms is included in (i), to allow for pole scatter and the different pick-up time of the
level detectors.
Any existing indications are not automatically erased for a SOTF trip. Start tests
with SW2 to the right (nearly all applications will have this setting). Tests should be
done using A–N faults and if desired can be repeated on B–N and C–N.
To check (i). Go from a poles dead condition to a fault condition with the required
level detector conditions.
Confirm that SOTF indication is obtained and that the trip time is 40 – 50ms
approximately.
To check (ii), go from a pole dead condition to a fault condition in Zone 1
(preferably close up), confirm that SOTF indication is obtained and that the trip
time is less than 30ms approximately.
If busbar VT’s are to be used, the opto isolator input for breaker open (Terminals
A3–4) should be energised. Faults can then be applied in the normal way giving
SOTF indication and the times already indicated. Do not forget to remove the opto
isolator signal after completing the tests.
If SW2 is to be set to the left, set it there and confirm that after the next SOTF trip,
another cannot be obtained for the 110s (try the first trip after poles dead for 120s
and the next after 100s).
Normal trips will occur when SOTF trips do not. If this check is being done for
busbar VT’s, the opto isolator signal should be switched off and back on for the
appropriate time in between each trip to obtain correct operation.
iii) With SW1 to the right (switch-on-to-fault operation via current and no volts level
detectors) repeat check (i) but with the miniature circuit breaker opto energised
(case terminals A1/A2) – switch-on-to-fault will be blocked.
iv) With SW1 to the left (switch-on-to-fault via comparators) repeat check (ii) but
with the MCB opto energised (case terminals A1/A2) – switch-on-to-fault will be
blocked.