Areva MiCom P120, Technical Manual

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Application Guide P12x/EN AP/A96
MiCOM P120/P121/P122/P123
Page 67/80
27. TRIP CIRCUIT SUPERVISION (P122 & P123 ONLY)
The trip circuit extends beyond the relay enclosure and passes through more components,
such as fuse, wires, relay contacts, auxiliary switch contact and so on.
These complications, coupled with the importance of the circuit, have directed attention to its
supervision.
The simplest arrangement for trip circuit supervision contains a healthy trip lamp in series
with a resistance placed in parallel with a trip output relay contacts of the protection device.
27.1 Trip Circuit Supervision mechanism
The Trip Circuit Supervision function included in the MiCOM P122 and P123 relays is
described below:
WARNING: SINCE HARDWARE 5 (NAMED ALSO PHASE II), THE VALUES USED IN
THE CALCULATION OF THE EXTERNAL RESISTOR NEEDED FOR THE
TRIP CIRCUIT SUPERVISION HAVE CHANGED.
A logic input is programmed to the AUTOMAT. CTRL/CB Supervision/TC Supervision
function. The logic input is associated to the label Trip Circ within the AUTOMAT.
CTRL/Inputs menu. Then, this logic input is wired in the trip circuit according to one of the
typical application diagrams shown in the following example.
When the function TC Supervision is set to "Yes" under the CB Supervision sub-menu, the
relay checks continuously on trip circuit continuity whatever the CB status is CB opened or
CB closed. The function
TC Supervision is enabled when the trip logic output ( RL1 ) is not
energised. The function TC Supervision is not enabled when the trip logic output ( RL1 ) is
energised.
A 52 Fail (trip circuit failure) signal is generated if the logic input detects no voltage signal
during a time longer than the settable timer tSUP . See Chapter P12y/EN FT (User Guide)
and Chapter P12y/EN TD (Technical Data) for the settings.
As this function is disabled when the trip logic output ( RL1 ) is energised, this function is
suitable for use with the enabled relay latching logic.
The tSUP timer can be set according to the following table:
SETTING RANGE
MENU TEXT
MIN MAX
STEP SIZE
TC Supervision ? Yes No
tSUP 100ms 10s 50ms
tSUP 0
52 Fail
signal
&
Binary input
Trip Circ.
Tripping
Relay RL1
energized
P0037ENa
FIGURE 21: TRIP CIRCUIT SUPERVISION PRINCIPLE DIAGRAM