ABB SPAC 531 C User Manual And Technical Description page 37

The incoming feeder cubicle and the busbar
system are protected by one single feeder termi-
nal type SPAC 531 C3, which incorporates a
phase overcurrent relay module SPCJ 3C3 and
a control module SPTO 6D3, but no neutral
overcurrent module.
In the example illustrated in Fig. 16 the low-set
stage of the phase overcurrent module U1 (SPCJ
3C3) operates as back-up protection for the
outgoing feeders, whereas the high-set stage is
used for the protection of the busbar system.
The operation of the busbar protection has been
speeded up by means of blocking signals from
the phase overcurrent relays of the feeders. If
there is a fault on an outgoing feeder, the over-
current module of the feeder delivers a blocking
signal to the overcurrent relay module of the
incoming feeder cubicle. If the fault is in the
busbar system, no blocking signal is received
and the overcurrent relay module of the incom-
ing feeder cubicle delivers a tripping signal to
Switch SGB/SPCJ 3C3
1 0 no I> start to AR2
2 0 no I>> start to AR2
3 0 no I>> start to AR1
4 0 no block. BS 1 to t>
5 1 blocking BS 1 to t>>
6 0 no block. BS 2 to t>
7 0 no block. BS 2 to t>>
8 0 not in use
With above SGB and SGR switch settings the
output contacts of feeder terminal SPAC 531
C3 have the following functions:
Contact Function
X1/3-4 Opening 1 of CB (I>, I>>)
X1/6-7 Signal for final tripping (I> or I>>)
X2/1-2-3 Not in use
X2/4-5-6 I>> start and blocking signal to the phase overcurrent module of power
transformer high voltage side
X2/7-8-9 Not in use
X1/8-9-10 Self-supervision alarm (IRF)
X3/11-12 Opening 2 of CB (local control, remote control)
X3/13-14 CB closing
Since no auto-reclose functions are used in exam-
ple 5, the AR parameters can be set as follows:
Parameter Value Function
S78 0 Inhibits AR functions
V151 1 Stores the set parameter
the circuit breaker. Thus a relay time of about
100 ms is obtained in the event of short circuit
in the busbar. Due to its wide setting range the
high-set phase overcurrent stage is well suited
for starting the busbar protection.
Busbar protection based on blockings can also
be used when the outgoing feeder has a reverse
current infeed, provided the level of the reverse
current is below the setting of the high-set phase
overcurrent stage. Then the blocking signal
from the overcurrent relay module of the outgo-
ing feeder is taken from the high-set stage of the
protection.
The blocking signals to the contacts X2/11-12
of the busbar protection are routed to the high-
set stage of the phase overcurrent module by
setting the SGB/5 switch on the PC board of the
overcurrent module in position one (ON). The
other internal switches of the modules can be set
as shown in the following table.
SGR
0 no I> start to SIGNAL 3
1 I> and I>> trip to SIGNAL 1
0 no Iϕ> trip to TRIP output
0 not in use
0 not in use
0 not in use
0 no TRIP sign. to SIGNAL 1
0 no TRIP sign. to SIGNAL 2
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