ABB Relion SMU615 Technical Manual page 131

1MRS758407 B
SMU615
Technical Manual
A051097 V6 EN
Figure 85: Operating principle of the trip-circuit supervision with an external
resistor. The TCSSCBR blocking switch is not required since the
external resistor is used.
If TCS is required only in a closed position, the external shunt resistance can be
omitted. When the circuit breaker is in the open position, TCS sees the situation as a
faulty circuit. One way to avoid TCS operation in this situation would be to block the
supervision function whenever the circuit breaker is open.
Section 5
Supervision functions
125