FUNCTION CHARACTERISTICS
83
NG10 - Manual - 04 - 2022
Trip circuit supervision - 74TCS
Preface
The trip circuit can be monitored to signal possible anomalies that would lead to the missing opening
of circuit breaker when trip and/or operator command are issued.
Circuit interruption as well as missing of auxiliary voltage and/or coil faults are detected.
Supervision with one or two binary inputs can be select; depending on association of binary inputs,
the corresponding logic is automatically selected.
For this purpose the TCS1sideH and TCS2sideH for side H and TCS1sideL and TCS2sideL
for side H L (if two binary input are used) matching must be assigned to the selected binary inputs
inside the Set \ Ingressi \ Input IN1 and Set \ Ingressi \ Input IN x.
When a binary input is programmed for the TCS function, the IN1 tON, INx tON, IN1 tOFF and
INx tOFF time delays must be reset to zero and the Logic parameter must be set to Active-ON
inside the Set \ Inputs \ Binary input IN1 and Set \ Inputs \ Binary input INx menus.
Operation and settings
The 74TCS element may be enabled or disabled; to enable it, the 74TCS(H)Enableparameter must
be set to ON inside the Set \ Profile A(B) \ Profile A(B) side H \ Trip circuit supervision-74TCS for side
H and Set \ Profile A(B) \ Profile A(B) side L \ Trip circuit supervision-74TCS for side L menu.
Logical block (Block1)
If the 74TCS(H)-BLK1 enabling parameters for side H and the 74TCS(L)-BLK1 en-
abling parameters for side L are set to ON and a binary input is designed for logical block
(Block1), the concerning element is blocked off whenever the given input is active.
[1]
The
enabling parameters are available inside the Set \ Profile A(or B) \ Profile A(or B) side H \
I(H)> Trip circuit supervision side H - 74TCS side H \ Setpoints menus for side H and Set \ Profile
A(or B) \ Profile A(or B) side H \ I(H)> Trip circuit supervision side H - 74TCS side H \ Setpoints menus
for side L while the Block1 function must be assigned to the selected binary input inside the Set \
Inputs \ Binary input IN1(x) menus.
Two inputs supervision
With two binary input all malfunctions are detected (inclusive of mechanics faults).
The binary inputs are connected to the trip and to the 52b contacts.
The CB auxiliary voltage must be 36 V at least (twice the minimum threshold for every binary input).
The faulty condition is detected occurs if both the following conditions are filled:
A) The TRIP contact is closed (external protection relay tripped);
B) The circuit breaker is closed (52a closed and 52b open).
Because such conditions can arise with healthy circuit too (e.g. a trip command is issued by the
protection relay but the CB opening time is still in progress), to avoid untimely operations the previ-
ous condition are checked every 80 ms and the output is issued after a 2 s delay; outputs are reset
to zero if at least the A or B condition become false after 0.6 s delay.
[2]
Note 1 The exhaustive treatment of the logical block (Block 1) function may be found in the “Logic Block” paragraph inside CONTROL AND MONITOR-
ING section
Note 2 Following assumption are considered for the framework:
Logic: ON,
Timers t
ON
and t
OFF:
reset to zero
TRIP contact of the protection: DE-energized, No latched
TCS2s.ai
TRIP
+UAUX
-UAUX
52a 52b
52(H)
Pro-N
Binary input IN1
Binary input IN2
TCS1
TCS2
Towards 74TCS logic
Towards 74TCS logic
Trip circuit supervision with two binary inputs - 74TCS
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