Figure 459: Functional module diagram
TCS status
This module receives the trip circuit status from the hardware. A detected failure in
the trip circuit activates the timer.
Timer
Once activated, the timer runs until the set value of
Operate delay time
has elapsed.
The time characteristic is according to DT. When the operation timer has reached
the maximum time value, the ALARM output is activated. If a drop-off situation
occurs during the operate time up counting, the fixed 0.5 s reset timer is activated.
After that time, the operation timer is reset.
The BLOCK input can be controlled with a binary input, a horizontal communication
input or an internal signal of the relay program. The activation of the BLOCK input
prevents the ALARM output to be activated.
6.1.5 Application
TCSSCBR detects faults in the electrical control circuit of the circuit breaker. The
function can supervise both open and closed coil circuits. This supervision is
necessary to find out the vitality of the control circuits continuously.
Figure 460
shows an application of the trip circuit supervision function use. The
best solution is to connect an external R
ext
shunt resistor in parallel with the circuit
breaker internal contact. Although the circuit breaker internal contact is open, TCS
can see the trip circuit through R
ext
. The R
ext
resistor should have such a resistance
that the current through the resistance remains small, that is, it does not harm or
overload the circuit breaker's trip coil.
1MRS757644 H
Supervision functions
620 series
Technical Manual
867
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