Alstom SHPM 101, Service Manual

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SERVICE MANUAL R5888C
QUADRAMHO Chapter 5
Page 4 of 24
4.3 Initial checks, including self-check facilities
If the dc supplies are available on the panel they can be checked on test plug 1Z
red ringed terminals 5(+) and 6(–). If the supply is within the required operative
range it can be linked through to the relay. If the panel supply is not available, a
suitable supply could be connected to the relay side terminals 5 and 6 of the test
plug.
The bridge on terminals 10 of the 1Z test plug should be made and the relay
available green light emitting diode (LED) on module 6 should light. (Check that the
relay inoperative alarm contact C21–22 opens). If the dc is removed and
re-applied it will be seen that all the red LEDs on module 4 light while the relay
goes through its power up procedure and at the end of it, the relay available LED
lights. (A scheme option number must be selected see Figure 2). If three phase to
neutral voltages, each above 70% of 63.5 volts are connected to the relay side
terminals 1, 2, 3 and 4 of test block 1Z as shown in Figure 1, an additional self-
check on the comparators is made available if SW5 on module 4 is to the right
(see Figure 2). This feature can now be initiated by pressing and releasing the
reset pushbutton, when all the red LEDs, except power swing, will be seen to
briefly flash.
Alternatively, if the dc is switched off and then re-applied, when the power up
procedure has finished the self-check takes place and on careful observation it will
be seen that the red LEDs flash again and the relay available LED should light. This
will re-occur once every two weeks if the dc is left on and ac volts are present as
previously described.
All the following are monitored continuously when in a scheme option:
i) Internal dc voltage rails for +5V, +12V, +24V and –12V.
ii) The internal clock.
iii) The reference voltages for the level detectors.
iv) The processor running through its program.
In addition the ability of the comparators to count up in response to two square
wave inputs and reset is monitored during the additional self-check (which puts the
relay out of service for 80ms without affecting the relay available LED or alarm
contact unless a fault is found).
If a fault is detected in any of the above, the relay available LED will extinguish
and the problem analysis instructions in Chapter 6 should be consulted.
It should be noted that the inoperative alarm is given if the output relays are
inhibited by any means or if the voltage transformer supervision is set to block and
zero sequence volts are detected without zero sequence current.
4.4 Level detector checks
4.4.1 Voltage level detectors
Each phase to neutral input voltage is monitored and pick up of the level detector
is fixed at 44.45V
±
10%).
The scheme logic uses this information in:
a) The switch-on-to-fault feature (SOFT).
b) The decision to enable the memory and to output it.
c) The decision to perform the self-check (if selected).