ALARM
t
Timer
BLOCK
TCS
status
TCS_STATE
Figure 738: 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.
shows an application of the trip circuit supervision function use.
Example of both mechanical (on the left) and static (on the right) outputs TCS
connections are shown.
The mechanical outputs (PODPx) are used in both AC or DC circuits, and
polarity is insignificant. The static outputs (SPOx) can be used in DC only
and polarity must be correct.
The best solution is to connect an external R
ext
shunt resistor in parallel with the
circuit breaker internal contact as shown with the dashed line. This way, although
the circuit breaker auxiliary 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 circuit
breaker coil remains small, that is, it does not harm or overload the circuit breaker's
trip coil if the trip is latched/locked-out.
1MRS759142 F
Supervision functions
REX640
Technical Manual
1303