Memory Feature Check; Check On Function Of Sw4; Trip Test Function Check - Alstom SHPM 101 Service Manual

SERVICE MANUAL
QUADRAMHO
Note: If SW1 is set to the left the fault current may be reversed to confirm Zone 3
comparators are part of the SOTF feature.
4.15 Memory feature check (synchronous polarising)
The memory is mainly to deal with 3 phase close up faults but is made to run out
when any voltage level detector resets or when any comparator operates. There is
nominally 8 cycles of memory polarising which is all derived from C phase volts.
The memory is re-connected 140ms after all voltage level detectors pick up and
comparators have reset.
We thus have to satisfy the above conditions and make the relay behave as though
it is seeing a 3 phase close up fault.
This is achieved by applying a close up C–N fault after removing the A and B
voltage inputs and connecting test plug 1Z terminals 1, 2 and 3 together
(see Figure 1).
If the dwell time of the trip contacts is now measured this will give a measure of the
memory time.
On 50Hz the time measured should be 180 – 220ms.
On 60Hz the time measured should be 150 – 200ms.
With these voltage connections a self-check may bring up the relay inoperative
alarm. This condition will disappear when the voltage connections are normal and
another self-check is made. Remember that a self-check is made every time the
reset button is pressed if the feature has been selected by SW5 and all voltage
level detectors are picked up.
4.16 Check on function of SW4 (if auto-reclose is used)
If in schemes 02 to 09 set SW6 to the left.
Apply a 3 phase Zone 1 fault and check that the block auto reclose contact
(terminals B25–26) closes when SW4 is set to the right and does not when SW4 is
set to the left. Set the switch to the desired position.
Note: Some customers may only consider it necessary to use test option 57 to
check that the switch position is being correctly put into the scheme logic.
4.17

Trip test function check

If the code selection switches are set to 88 and the reset pushbutton is pressed, the
trip outputs given are controlled by SW1–5.
SW1 to the right gives trip C
SW2 to the right gives trip B
SW3 to the right gives trip A
SW4 to the right gives trip 3 phase
SW5 to the right gives any trip
These should be checked so that if a trip test is carried out later, the engineer will
be aware of what is necessary and will have confidence that the required contacts
Terminals B13–14
B15–16
Terminals B9–10
B11–12
Terminals B5–6
B7–8
Terminals B17–18
B19–20
Terminals B21–22
B23–24
R5888C
Chapter 5
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