Alstom SHPM 101 - Section 4 TEST PROCEDURE; 4.5.3 Phase faults; 4.5.2 Zone 1 ext reach checks; 4.5.3 Zone 2 reach tests

SERVICE MANUAL R5888C
QUADRAMHO Chapter 6
Page 5 of 12
iii) Phase faults
The appropriate loop impedance is now:
2 x K14 (K1 + K2) (K11 + K12 + K13)
ohms
I
n
Carry out the tests as for the ground faults, starting with A-B and proceeding to
B-C and C-A faults.
Note: If using a ZFB, VTS indication will now be obtained.
4.5.2 Zone 1 ext reach checks
Select option 08 and check the RESET ZONE 1 EXT opto isolator is not energised.
The Zone 1 reach is now extended by K15. The reach should be checked as in
Section 4.5.1.
4.5.3 Zone 2 reach tests
Select option 00.
When checking Zone 2 reaches the effect of the expansion of the reach when any
trip occurs may be apparent.
If a fault is applied less than 5% outside the Zone 2 boundary and inside the Zone
3 boundary, then if Zone 3 times out, giving a trip output, Zone 2 indication will
also be seen if the fault is maintained for Zone 2 time after the Zone 3 trip occurs.
The ground fault loop impedance required is:
(K1 + K2 + K4 + K5 + K6) (K21 + K22) K24
I
n
and for phase faults the loop impedance required is:
2 x K14 (K1 + K2) (K21 + K22) K24
ohms
I
n
the reach for each type of phase-ground and phase-phase element of the relay
should be checked as in Section 4.5.1.
4.5.4 Zone 3 reach checks
If t
Z3
has been set to ∞, the switch must temporarily be moved to the left to enable
the reach checks to be done. Zone 3 has the facility for setting forward and
reverse reaches, on the line angle, independently. There are two different shapes
available as selected by the customer when ordering the relay. These are lenticular
or a quadrilateral for ground faults.
The presence of the lenticular shape is indicated on module 3 by a switch labelled
a/b which controls the aspect ratio as illustrated on the frontplate; when a/b is set
to 1 the characteristic is circular. For this test set a/b = 1 if fitted.
The presence of the quadrilateral shape is indicated on module 1 when switch (K3)
for the setting of the resistive forward and reverse reach of Zones 1, 2 and 3 is
fitted.
The ground fault loop impedance required for forward checks is:
(K1 + K2 + K4 + K5 + K6) (K31 + K32) K33
ohms
I
n