4
Block diagram
Fig. 1. Block diagram for the overcurrent relay module SPCJ 3C3.
I
L1
, I
L2
, I
L3
Measured phase currents
BS1, BS2, BS3
External blocking signals
BTS1
Blocking signal for the tripping of stage I>
BTS2
Blocking signal for the tripping of stage I>>
SG1
Selector switchgroup on the front panel
SG2
Function selector switchgroup for the operation indicators
SGB
Blocking signal selector switchgroup on the PC board and
starting signal selector switchgroup for the auto-reclose functions
SS1
Start signal of stage I>
TS1
Trip signal of stage I>
SS2
Start signal of stage I>>
TS2
Trip signal of stage I>>
AR1, AR2
Start signals for auto-reclose functions
Y
Yellow indicator, starting
R
Red indicator, tripping
NOTE!
All input and output signals of the relay module
are not necessarily wired to the terminals of any
protection relay incorporating this module. The
signals wired to the terminals are shown in the
diagram illustrating the interchange of signals
between the various modules of the protection
relay.