Alstom SHPM 101, Руководство по обслуживанию

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SERVICE MANUAL R5888C
QUADRAMHO Chapter 5
Page 7 of 24
The voltage supply to any test set working off 3 phase supplies should be checked
for correct phase rotation.
The test blocks should be connected as shown in Figure 1.
The particular scheme option numbers should be selected (if 08 or 09 is selected
energise RESET Z1 EXT. opto isolator input) and SW3 controlling the ability of the
VTS to block comparators should be set to the left (ie. not blocking). It may also be
advisable to set SW9 to the left. This disables the power swing blocking feature.
Note: Refer to 4.9 as it may be convenient to combine timing checks with the
reach checks.
If busbar VT’s are fitted and the breaker open opto isolator input is energised, then
the SOFT feature will be operational all the time. In the POR scheme the same input
may also be used as part of the weak infeed feature.
Terminal A3 should in these circumstances be isolated and only energised when
required during commissioning.
4.5.2 Ground faults Zone 1
Commence with connections for an A–N fault. To establish confidence in operation
a close-up fault with adequate source impedance to limit the current should be
applied. The LED marked A should light followed by Z2 and Z3 if the fault is left
on. (Assuming t
Z3
is not set to 00).
The current should then be reversed to check that operation does not occur, except
for Z3 which always has some reverse reach.
The appropriate loop impedance should now be presented to the relay
K14 (K1 + K2 + K4 + K5 + K6) (K11 + K12 + K13)
ohms
I
n
or the nearest higher figure available.
Make small step adjustments to the impedance, only presenting them for less than
Zone 2 time to the relay and determine the highest impedance which gives
instantaneous illumination of the A LED (If a low Zone 2 time is set it may help to
temporarily increase it).
The measured impedance should be within 10% of the calculated value assuming
the angle of the impedance presented is within 5
°
of
θ
Ph
and
θ
N
on module 7 of
the relay. Check that the appropriate contacts operate for single or three phase
tripping as selected (see Figure 4 for the external connections and which contacts
will operate). In particular check the any trip contacts on test block 1Z terminals
7 – 8. They have been isolated from case terminals B21 and B22).
Repeat the tests for B–N and C–N including the directional checks.
Note: The indications are automatically reset when a new trip output is obtained
but it may be easier to understand what happens during commissioning by
using the manual reset on Module 4.
If
θ
Ph
and
θ
N
differ by more than allowed above then the vector sum of the
coarse phase reach and the neutral compensation must be found to give
the basic ground fault loop impedance and the required ground fault
angle. This must be applied to all zones by use of the appropriate zone
multiplier.