Siemens SIPROTEC 4 7VK61 Manual page 145

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Figure 2-59
TR Trip relay contact
CB Circuit breaker
TC Circuit breaker trip coil
Aux1 Circuit breaker auxiliary contact (NO contact)
Aux2 Circuit breaker auxiliary contact (NC contact)
U-CTR Control voltage (trip voltage)
U-BI1 Input voltage of 1st binary input
U-BI2 Input voltage of 2nd binary input
Supervision with two binary inputs not only detects interruptions in the trip circuit and loss of control voltage,
it also supervises the response of the circuit breaker using the position of the circuit breaker auxiliary contacts.
Depending on the conditions of the trip contact and the circuit breaker, the binary inputs are activated (logical
condition "H" in the following table), or short-circuited (logical condition "L").
A state in which both binary inputs are not activated ("L") is only possible in intact trip circuits for a short tran-
sition period (trip relay contact closed but circuit breaker not yet open).
A continuous state of this condition is only possible when the trip circuit has been interrupted, a short-circuit
exists in the trip circuit, a loss of battery voltage occurs, or malfunctions occur with the circuit breaker mecha-
nism. Therefore, it is used as supervision criterion.
Table 2-6
No Trip Contact Circuit Breaker
.
1 open ON
2 open OFF
3 closed ON
4 closed OFF
The conditions of the two binary inputs are checked periodically. A query takes place about every 500 ms. If
three consecutive conditional checks detect an abnormality, a fault indication is output (see
repeated measurements determine the delay of the alarm message and avoid that an alarm is output during
SIPROTEC 4, 7VK61, Manual
C53000-G1176-C159-5, Edition 05.2018
Principle of the trip circuit supervision with two binary inputs
Condition table for binary inputs, depending on RTC and CB position
Aux 1
closed
open
closed
open
Aux 2 BI 1 BI 2
open H L
closed H H
open L L
closed L H
Functions
2.7 Monitoring Functions
Dynamic State Static State
Normal operation with circuit
breaker closed
Normal operation with circuit
breaker open
Transition or Malfunction
malfunction
TR has tripped successfully
Figure 2-60). The
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