1
PSM
2
Rs
(+)
(-)
HW
S W
PO1
TCS1
IS
V
IS: Constant current generator.
Current level ~ 1,0 mA (I
c
)
V: Transient Voltage Suppressor
Breakdown Voltage 380 to 400 VDC
I
c
CBPOS_open
TCSSCBR
TCS_STATE
BLOCK
ALARM
IEC13000026-2-en.vsd
GUID-6B09F9C7-86D0-4A7A-8E08-8E37CAE53249 V3 EN
Figure 67: Operating principle of the trip-circuit supervision without an external
resistor. The circuit breaker open indication is set to block TCSSCBR
when the circuit breaker is open.
Trip-circuit monitoring and other trip contacts
It is typical that the trip circuit contains more than one trip contact in parallel, for example
in transformer feeders where the trip of a Buchholz relay is connected in parallel with the
feeder terminal and other relays involved.
1MRK 511 286-UUS A Section 9
Secondary system supervision
179
Application manual